When Albert Einstein died in 1955, he left behind a trove of 80,000 letters, papers, and articles. In December, Princeton University Press announced the launch of The Digital Einstein Papers, a website where anyone can access more than 30,000 of those documents. (Most of Einstein's writings have been translated from German into English.)

Einstein's documents are fascinating, ranging in topic from blurbs of Bertrand Russell books to screeds on why final exams are a "nightmare." But one of the most informative pieces in the collection was not authored by Einstein himself. It's a biographical sketch of the young Einstein and his family, written with depth, humor, and economy, by Maja Winteler-Einstein, Albert's younger sister. 

As it happens, her insider account is filled with tales of the family's entrepreneurial highs and lows. Here are three examples:

1. The Family Grain Fortune 

This business began as a modest bakery that Einstein's maternal grandfather, Julius Koch, started with his brother. Their wives were in charge of the cooking. Both couples lived under one roof in Canstatt, Germany. 

What kind of entrepreneur was Koch? He was more of a decisive action-taker than a high-concept thinker. He "possessed a distinctly practical intelligence and a great energy," writes Winteler-Einstein. "Theorizing was completely foreign to him."

Her account doesn't provide exact dates, but it's safe to surmise that the business was a going concern in 1858, when Einstein's mother, Pauline Koch, was born.  

2. A Failed Venture in Electricity

Einstein's father, Hermann, co-founded a business installing electric lighting in 1882. The co-founder was Hermann's younger brother, Jakob. Albert was two at the time, turning three in March. Maja was one. 

Her description of these days paints a picture of how Jakob and Hermann had different mentalities as entrepreneurs. She holds both brothers responsible for the eventual failure of the seemingly promising business, launched at a time when "all the world was beginning to install electric lighting."

Problems arose, she writes, because Jakob got caught up in a quest to produce his own invention in the realm of electric lighting--a project that required a larger manufacturing plant and significant funding. Although wealthy uncle Julius, the baker-turned-grain entrepreneur, was able to supply plenty of capital, the business ultimately failed.

Hermann, for his part, may have been too contemplative to hold Jakob's feet to the fire. "And since everything could always be looked at from a new point of view, that particularly entrepreneurial trait of being decisive at the right moment about the right matters was impaired," writes Winteler-Einstein of her and Albert's father.

Despite this ineffective leadership mix of brothers quixotic and tolerant, the business still managed to survive 14 years, buoyed by the strength of sales in Italy--to the point where both brothers and their families moved to Milan in 1894.

But just two years later, sales dwindled, and they had to liquidate the company. The brothers amicably went their separate ways.

3. Finding New Niches in Power

While Jakob took an engineering job with a large company, Hermann "could not bring himself to take the same step and relinquish his professional independence," writes Winteler-Einstein.

His first venture was another electrical factory based in Milan. It only lasted for a few years, unable to survive competition from established players in the burgeoning electricity space. 

For his next venture, a heavily leveraged Hermann found a new niche in the electricity vertical, installing power stations that could supply lighting to entire villages. This time, the business did well. But according to Winteler-Einstein, the stress of depending on financing from others affected his health.

"How much more difficult this is to bear than the merely occupational dependence on one's employer!" she writes. In October 1902, he suffered a "serious heart ailment" and died.

Perhaps the most enjoyable parts of Winteler-Einstein's family sketch are descriptions of how young Albert, like his entrepreneurial ancestors, was persistent about his tasks. As a boy, he routinely took the time to build houses of cards that were 14 stories high.

That's not a typo. Fourteen stories. "Anyone who knows how much patience and precision is required to build card houses three or four stories high will be amazed that a boy not yet 10 years old was able to build them as high as 14 stories," writes Winteler-Einstein. 

This persistence would spill over into what a contemporary biographer-hagiographer would call Einstein's 10,000 hours of practice. As a teen, he spent school vacations in long periods of isolation, attempting to prove classic mathematical theorems for himself.

This time period is also when Einstein first found fruit in independent thought. "For days on end he sat alone, immersed in the search for solution, not giving up before he found it," writes his sister. "He often found proofs by ways that were different from those found in the books."

His uncle Jakob, the entrepreneur-turned-large-company-engineer, often supplied Einstein with advanced mathematical problems, which Einstein inevitably solved. On one occasion, he even found an entirely original proof for the Pythagorean theorem. 

And all this is just a sampling of what you'll find in Winteler-Einstein's sketch of her brother. It's a flattering but nonetheless illuminating look at the young life of a nonpareil problem-solver, and the entrepreneurs in his family tree.