Nothing beats the economics and ingenuity of a great dual-use product. On a scorching February day, Moses Kizza Musaazi stands behind the latrines at Mpigi UMEA Primary School, describing the features of his portable incinerator. The mud at his feet is red. So are the uniforms of the children who surge and subside in waves as he delivers his tutorial.

Musaazi is telling me about the unit's three-chamber design, which allows it to heat to almost twice the temperature of other incinerators manufactured here, in his native Uganda. He points out a fat pipe running into the girls' toilet stall to facilitate the discreet disposal of sanitary pads. Smiling broadly, Musaazi slides out a metal panel that bisects the pipe. "Most of the time when the incinerator is burning, this stays in," he explains. "But if you remove it, the smoke goes back up into the bathroom and drives away the flies."

What I like about the incinerator, besides the fly thing, is that it represents a kind of turnkey thinking about human suffering. In Uganda, where more than 50 percent of the population survives on less than $1.25 a day, social problems abound. A holistic innovator, Musaazi attacks those problems in clusters. The origin problem in this particular cluster is girls' abandoning school when they reach puberty. They do so because 1. They cannot afford sanitary napkins 2. They cannot privately dispose of sanitary napkins and 3. They cannot wash, because school bathrooms—walled-off holes in the ground—lack running water.

Musaazi's solution to Problem No. 1 is the MakaPad, a sanitary napkin made of papyrus and paper waste. It costs less than a third as much as global brands. Introduced in 2006, the product accounts for roughly half the revenue of his Kampala-based company, Technology for Tomorrow, or T4T. Musaazi also designed the incinerator, which addresses Problem No. 2, as well as a larger version for medical waste sold to hospitals and health centers. Musaazi attacks Problem No. 3 with rainwater-harvesting tanks and solar water heaters.

The water tanks are constructed from curved, interlocking dirt bricks, which Musaazi created as an alternative to traditional fired bricks, whose baking consumes whole forests. He also uses his bricks to build granaries, meant to generate income for peasant farmers year round and help schools store maize for affordable lunches. Those lunches might be prepared on one of Musaazi's hybrid cook stoves, which by the way also heat water for use in kitchens. Did I mention that steam from the incinerators produces power?

"I think things through from beginning to end, because when people need this, they will also need that, and there is always great need, and to waste something is a catastrophe," says Musaazi, a calm and courtly man of 60 whose motto—emblazoned on his office doors and on the dashboard of his Toyota minivan—is the Bugandan phrase Gakyali Mabaga ("So little done. So much more to do."). "If I dig a pit latrine, I should be able to use the dirt to make bricks. If I build a water tank, why not make it a little bigger so the person can sell the excess water and have an income?"

When Western entrepreneurs engage in the developing world, they typically target a single (intractable, overwhelming) problem. Musaazi, by contrast, grapples with a range of Uganda's myriad ills. He is constantly expanding his portfolio of simple, inexpensive technologies because his country's population continues to expand, creating new problems and deepening old ones. Uganda has the world's second-highest birthrate, with an average 6.7 children per family and a median age of just 15.

Few subjects ruffle Musaazi, who exhibits none of the nervous energy or intensity typical of Western entrepreneurs. But when discussing overpopulation, he accelerates from melancholy to cynicism in no time flat. "We pick up so much from the West in terms of wanting the clothing, wanting the iPhones," he says as we sit in traffic, gulping exhaust until I start to feel like one of those bathroom flies. "Why don't we pick up the idea that the last three American Presidents had no more than two children, and Clinton only had one?"

Many of Musaazi's customers are nongovernmental organizations, or NGOs, and other philanthropic groups that share his concern. Among them is One School at a Time, a nonprofit based in Eldorado Springs, Colorado, that rehabilitates Ugandan schools and helps local people manage the schools better. "People coming from the West want to bring our own technologies," says Bay Roberts, the organization's director, who has deployed T4T's brick presses and rainwater-harvesting systems for seven years. "But those may not make sense culturally and can't be maintained or fixed once we leave.

"Moses is fantastic, because he's a Ugandan thinking up local solutions," says Roberts. "He understands the culture. He understands the poverty. And he's coming up with these smart, simple technologies that work."

The drive to Makerere University from downtown Kampala takes 15 minutes and 10 years off my life. Ugandan traffic resembles a countrywide game of chicken, with real chickens (and cattle, goats, and dogs) sauntering across the road for extra points. Men in suits, women cradling infants, and the occasional nun perch composedly on the backs of ubiquitous motorcycle taxis, called boda bodas. The roadsides are clogged with hawkers of second-hand clothes, potatoes, furniture, religious medallions, and anything else that can be sold, bought, and perhaps sold again. More-urban areas teem with tiny businesses marketing a life cycle of services from birth (Jolly and Lowly Primary School) to death (Curious Funeral Services).

T4T resides in the Technology Development and Transfer Centre, a deceptively drab structure in the shadow of the university's College of Engineering, Design, Art, and Technology. (In addition to running the business, Musaazi is a lecturer in electrical engineering here. Makerere donates the space but is not otherwise connected to T4T.) Eleven years ago, Musaazi and a student crew erected the building as both home and showplace for his research. It is constructed from the interlocking bricks; in front stands an incinerator modified to power a small generator with steam. At the back, a 30,000-liter tank collects rainwater from the roof and pumps it inside, a silent reproof to the engineering building, whose cascading runoff has gouged a narrow moat in the dirt track between itself and its diminutive neighbor. "This building is the only one on campus that is self-sufficient in terms of water," says Musaazi. "The university uses the main water supply, and sometimes the machinery breaks, and they announce that for the next three days, we will not have water. But I always have my flush toilets."

Inside the building, T4T's lab is indistinguishable from a storage room, save for a few rudimentary instruments used for quality testing MakaPads. Mounted on the walls and suspended from the ceiling of Musaazi's office are several iterations of a light he has engineered to run off a car battery. He uses them for backup during electrical failures, of which we experience two in the time we sit talking. "Their power consumption is very low, and the battery can run for three weeks," says Musaazi, who has sold about 150 of the lights, with which he continues to tinker.

On this day, as he enters the building, Musaazi is accosted by a small boy with a stained blue shirt and gappy grin. Steven, 6, is the son of a campus security guard; Musaazi pays his school fees. Musaazi bends down to catch the boy's request: He needs money for four schoolbooks, at 120 shillings (around 5 cents) each. "I tested him: What is the total cost of the books?" says Musaazi, as he extracts a handful of coins from a plastic bottle concealed in a battered filing cabinet and hands them to the boy. "He answered correctly, so I am giving it to him."

Musaazi supports Steven and 11 other children and young adults from poor families as a broad gesture of appreciation for the government scholarships that put him through Uganda's top primary and secondary schools. Always "clever" (he prefers that designation to "brilliant," the common accolade among those familiar with his work), Musaazi grew up in circumstances that did not portend success. His father, a bus driver, died when Musaazi was a month old, his mother nine years later. For the next few years, he lived with an aunt, who "for every single mistake made by a child would pull out the cane."

The aunt stamped out any entrepreneurial embers before they could ignite. Musaazi's best friend sold pancakes, which earned him enough to buy shoes—an unheard-of luxury in their village. "My aunt was afraid I was going to be tempted by money and drop out of school," says Musaazi. "You get money; you get shoes; you leave school and sell more pancakes."

In 1979, Musaazi—who has a doctorate from the University of London—landed at Makerere. But university jobs in Uganda are not well paid, and he anguished over affording top-notch educations for his own four children. To supplement his income, he tutored students in math and opened a small business making roof tiles.

Then, in 1985, Musaazi returned to his village to visit the graves of his parents and two of his brothers. There, he found the lush hardwood forests virtually wiped out, burned in the ubiquitous rough-hewed kilns that fire clay bricks for Uganda's construction trade. In that Lorax moment, the first of Musaazi's inventions was born.

Mohamed Walusimbi remembers burning trees. "I started doing this work in 1954, and now I think, My God, how many have I destroyed?" he says through an interpreter. Now 78, Walusimbi still works as a mason, and today he is constructing a wall on the grounds of Masooli Primary School, on the outskirts of Kampala. Forehead glistening beneath a red skullcap, he demonstrates how each brick nestles into the ones below and beside it. "This is a much better way to go," says Walusimbi.

In a clearing surrounded by low-slung school buildings, two reed-thin men in baseball hats and mud-stippled shirts work the press, one filling a mold with a thick porridge of soil mixed with smidgens of cement and water, the other raising a heavy metal lever and swinging it down hard to chunk out a brick. In 1993, Musaazi bought a version of the machine from a company in Nairobi for $200 and spent another $100 modifying it to produce the groove-and-tongue-shaped blocks. Unlike traditional clay bricks, Musaazi's do not require firing but dry when left stacked in the sun for four hours. Because of their shape, they require just a thin icing of mortar.

"Whenever someone gives money to a school for construction, the schools are asked to contribute in making bricks, so they cut down trees to fire them," says Musaazi as he briefly commandeers the lever. "In the end, you have a building but no trees."

The bricks, like Musaazi's other inventions, are examples of "appropriate technology," an idea introduced by the economist E.F. Schumacher in his 1973 classic Small Is Beautiful. Schumacher championed sustainable, low-cost, high-human-labor production methods that blend science with local knowledge. Musaazi says his bricks—in addition to their environmental benefits—cost 40 percent less to use than do fired bricks because workers make them on-site, so there are no transportation costs, no time lost between production and use, and no bricks broken during shipping. The savings also include materials costs: The bricks require little cement to produce and much less mortar than do their traditional counterparts.

Musaazi also designed a curved version of the bricks to build water tanks, which unlike the metal and plastic versions sold throughout Uganda do not rust and cannot be punctured by thieves. He sells the brickmaking machines for $1,500 to companies, individuals, and NGOs or provides construction services using the press. Whenever possible, he markets brick construction and a tank together, sinks the tank underground, and uses the excavated dirt to make bricks. Musaazi estimates he has constructed 850 buildings, including private homes and the pristine new health center here at Masooli.

In one way, though, Musaazi remains a prophet unrecognized in his own land. Makerere University has yet to adopt any of his technologies. Musaazi estimates that simply installing a rainwater system would save the university $100,000 a month. Even more frustrating: The engineering faculty—which trains the country's civil engineers and architects—teaches only traditional methods of construction, ignoring the new, sustainable model visible through its windows.

"If a civil engineer does not study this product in university, he cannot recommend it," says Musaazi. "He says the teacher did not teach it to me, so I am not so sure it is good. If someone is building a house and the architect does not specify my bricks, he won't use them."

A wide bandage spans the brow of Ibrahim Rumanyika. In a perverse way, it is a testament to Musaazi's success.

The Kyaka II refugee settlement in western Uganda houses roughly 16,000 people in mud huts connected by a road that is mostly rut. Ibrahim arrived here with a younger brother in 2003, fleeing the Second Congo War. Since 2007, he has supervised the settlement's MakaPad plant, which employs 45 refugees earning as much as $200 a month. It is by far the settlement's most substantial employer, "so people in the village perceive that we are rich," explains Rumanyika, who was attacked for his money, which pays for his brother's boarding school.

Rumanyika escorts me around the compound, explaining the process by which every month, 167 kilograms of papyrus chopped from a nearby swamp become 100,000 sanitary pads. Virtually all are bought by the office of the United Nations High Commissioner for Refugees, or UNHCR, which distributes them here and at other Ugandan settlements. Workers peel the thick green stalks and pound them into fiber, then mix them with wet paper waste, donated by NGOs and businesses, to create a slurry that is dried on frames laid on wooden racks in the sun. Other workers remove the stiff, dried sheets; slide them through softening machines (designed by Musaazi); cut them to size; and seal them in polyethylene imported from China, using an electric sealing machine (modified by Musaazi). Finally, the pads are sterilized in plastic buckets under ultraviolet lights.

It is a surprising business in a country where discussion of menstruation is taboo. Sexual predators target children of reproductive age, and some girls fear their pads or rags will be stolen and used for witchcraft. Most African men know nothing of the subject and want to keep it that way. Musaazi, married nearly 40 years and with a grown daughter, claims he had never seen a sanitary pad until 2003 when "I was at a meeting at the Kampala Sheraton and a woman threw one in my face."

That woman was Katherine Namuddu, the now-retired associate director of the Africa Regional Office at the Rockefeller Foundation. Since the early 1990s, Namuddu has worked to improve African girls' access to education, critical to reducing poverty. She latched on early to the importance of providing affordable sanitary pads and a method for their disposal. Musaazi was in the audience when she described the problem for a group of businessmen, whom she pelted with pads as a humorous wake-up call.

At Namuddu's behest and backed by $78,000 from the Rockefeller Foundation, Musaazi embarked on a two-year research and development odyssey, during which he experimented with materials including water hyacinth (decays too quickly) and elephant grass (requires boiling to break down) before settling on papyrus. "I was very impressed with what he came up with, especially after visiting his first setup at the university, where he had these poor women doing the process and earning extra money," says Namuddu.

Namuddu and Musaazi had counted on the Ugandan Ministry of Education's buying MakaPads and distributing them to students. Musaazi had already piloted the product at 12 schools. But the ministry shrugged them off. Then the Rockefeller Foundation project came to an end, leaving Musaazi to market MakaPads as best he could. A local newspaper wrote about the pads, "and the very next day," Musaazi says, "UNHCR knocked on my door and said, 'I think you have what we've been looking for.' "

In Uganda, the UNHCR is responsible for 40,000 girls and women from ages 12 to 49 living in Kampala and eight refugee settlements. "Up until then, the refugees had been using cloths and rags and nothing," says Maria Mangeni, a community services assistant at the organization. "As in, You dig a hole in the ground and sit right there for three days." Shortly before hearing about MakaPads, Mangeni had traveled among the settlements surveying conditions there. "At that time, we were giving them cotton cloth," says Mangeni. "I saw some of the cloth being used for children's clothes and head scarves. The women said, 'Yeah, how can I use that nice cloth for my monthly period when I can just get a rag?' "

UNHCR immediately ordered 50,000 packets of 10 pads each, an order Musaazi was woefully unprepared to fill. "We were patient," says Mangeni. "I knew we had to do this." Last year, 85 percent of women in the settlements received MakaPads; this year, Mangeni expects to hit 100 percent. UNHCR offices in Kenya, Sudan, and the Democratic Republic of the Congo have expressed interest in setting up their own factories, although production is limited by the availability of papyrus.

Musaazi incorporated T4T in 2007 at the request of UNHCR, which preferred to do business with a company rather than an individual. Today, T4T runs four factories, including one in Gulu District in northern Uganda. That facility, a partnership with a Pentecostal church, employs mainly workers infected with HIV/AIDS. "They are former abductees of the Lord's Resistance Army who were raped or made wives to the rebels," says Juliet Nakibuule, Musaazi's supremely efficient general manager. "We ask employees at that site to name a backup team: a sister or parent we can train to do your job. That way, if you fall sick and can't work, the money still goes to your family."

Musaazi wants to court MakaPad customers beyond the UNHCR, which buys 90 percent of production. He continues to run at the Ministry of Education as well as NGOs. The consumer market is a longer shot: "The biggest hurdle is convincing the public that a product made by a local person is as good as or better than something imported," says Musaazi. Still, he recently ordered more attractive packaging from China. And he plans to deploy three-wheeled motorcycles towing carts filled with pads in the cities and villages, as well as a team of door-to-door saleswomen. "We already have one girl who walks around singing, 'Pads, pads, pads for sale,' like a hawker," says Musaazi.

By 10 A.M., Nicholas Kasekende has been at Cozy-Tech Engineering Works for several hours, performing his usual role of supervisor/babysitter. Kasekende, Musaazi's energy systems manager, spends much of his time standing around chaotic, cacophonous machine shops like this one because he knows the moment he leaves, workers will abandon T4T's project for someone else's. "They take on too many jobs, so if the customer isn't right there watching, their work won't get done," says Kasekende, whose blue overalls belie his management position. He divides the company's manufacturing orders—mostly for the incinerators—between this plant and a plant some distance away on the logic that power failures are unlikely to strike both locations at once, so at least part of the work is always progressing.

Kasekende pays the machine shops' owners but also slips cash to individual workers to guarantee their attention. "An employee who works on the incinerators comes late because he has got a piggery project at home," he explains above the shriek of electric saws. "I told him I need you here. I will pay you an extra 50,000 shillings to come on time."

Conducting business in Uganda is a perpetual war with inefficiency and corruption. Officials solicit bribes, electricity is spotty, traffic jams eat up hours, torrential downpours stall work, and people blow off appointments or simply can't find them because there are few street signs. Musaazi leaves home by 6 a.m. and spends his days pinballing among construction sites, MakaPad plants, the university, and customer meetings, not returning until 11 at night.

If the work can be frustrating, it is also not especially lucrative, at least at T4T's current scale. The company, which employs close to 250 people, most of whom make MakaPads, has revenue of roughly $300,000. (For comparative purposes, sales at companies on a list of fast-growth firms in Uganda range from $400,000 to $1 million, according to KPMG and Monitor Publishing, which compiled the ranking.) Musaazi owns 51 percent of T4T. The rest is divided among Nakibuule, Kasekende, and three of the entrepreneur's four adult children.

Musaazi genuinely doesn't seem to care about money. He has lived in the same on-campus faculty townhouse for 27 years, sharing the premises with the business of his wife, Sarah, who owns three small cafés and does a thriving side business baking wedding cakes.

T4T is generally profitable, but when it runs short of money, Musaazi opens his wallet. He has never taken a bank loan, although he considered doing so to fund the expansion of MakaPads into Kenyan refugee camps—a project that has temporarily stalled.

Occasionally, Musaazi will accept a job just for the intellectual challenge. That's why he designed a metal container that seasons wood for furniture making. At Erimu, a furniture company outside Kampala, production manager Cyprian Nsengiyunva hauls open the door to one container to reveal 400 hunks of timber swathed in a miasma of smoke. "Before, it took three years for hardwood to dry," says Nsengiyunva. "Now, with these dryers, it takes just one month." Musaazi built a dryer for Erimu, then taught employees there to build more. "As payment, they made me a very nice bed," says Musaazi. "You have made a lot of money out of this," he tells Nsengiyunva. "I think you should also make me a stool."

On the day I am to leave Uganda, Musaazi takes me to the shore of Lake Victoria, where we sit in a deserted outdoor restaurant under a flapping canopy. As we lunch on fried tilapia and chips-I break down and follow his example, using my fingers to pluck silky white flesh from the filigree of bones-Musaazi walks me through his projections for T4T's myriad products. He has several new ones in the pipeline, including a product he asks me not to mention because he is applying for a patent. He will soon market a device that allows parents to precisely divvy up pills for children. In Uganda, very few medicines are distributed in pediatric versions, and typical pill cutters make a hash of quartering tiny tablets, leading to frequent over- and underdosing.

MakaPads are T4T's best shot at a blockbuster, Musaazi believes. "In Uganda alone, there should be eight million people using sanitary pads," he says, as rain starts to spatter the table. "We think we can capture 50 percent of that market, because so many people are poor. If we can sensitize people to the need for pads, then they should choose ours. That is our hope."

Musaazi gestures toward the churning water, metal gray beneath a glowering sky. Somewhere out there, he tells me, are the Ssese Islands, which he has never seen. "I never go on holiday," he says. "But if I had time, I would go there. I understand there are beautiful beaches. Maybe I could take a book. Maybe I could have a drink. I could lie down and rest. I have never just lain on a beach before."

The sky yawns, and the rain buckets down. We grab the chips and make a run for it.