When people ask Elon Musk how he learned to build rockets, he has a simple answer.
"I read books," he reportedly likes to say.
Musk, who was smart enough to get into a physics PhD program at Stanford and then drop out because it didn't seem that relevant to him, has always been hungry for the written word.
In its profile of the Tesla and SpaceX CEO, The New Yorker reported that he was picked on a lot during his South African childhood, and he would retreat into fantasy (J.R.R. Tolkien) and science fiction (Isaac Asimov) to cope.
As we'll see below, books have always been important to Musk: inspiring him as a child, giving him heroes as a young adult, and helping him to learn rocket science while launching SpaceX.
1. The Lord of the Rings, by J.R.R. Tolkien
Musk had a nickname when he was a shrimpy, smart-mouthed kid growing up in South Africa: Muskrat
The New Yorker reports that "in his loneliness, he read a lot of fantasy and science fiction."
Those books--notably "The Lord of the Rings" by J.R.R. Tolkien--shaped his vision for his future self.
"The heroes of the books I read always felt a duty to save the world," he told The New Yorker.
2. The Hitchhiker's Guide to the Galaxy, by Douglas Adams
Musk says he had an "existential crisis" when he was between 12 and 15, burrowing into Friedrich Nietzsche, Arthur Schopenhauer, and other moody philosophers to find the meaning of life.
It didn't help.
Then he came upon The Hitchhiker's Guide to the Galaxy, a comedic interstellar romp by Douglas Adams. In the book, a supercomputer finds the "answer" to a meaningful life is the number 42 -- but the question was never figured out.
This was instructive to a young Musk.
"If you can properly phrase the question, then the answer is the easy part," Musk said in an interview. "So, to the degree that we can better understand the universe, then we can better know what questions to ask."
3. Benjamin Franklin: An American Life, by Walter Isaacson
Musk has said that Ben Franklin is one of his heroes.
In Isaacson's biography, "you can see how [Franklin] was an entrepreneur," Musk says in an interview with Foundation. "He started from nothing. He was just a runaway kid."
Something about that is similar to Musk's story -- growing up in Pretoria, South Africa, going to school in Canada, transferring to the University of Pennsylvania, then using an invitation to Stanford's PhD program to land in Silicon Valley.
Musk's review: "Franklin's pretty awesome."
4. Einstein: His Life and Universe, by Walter Isaacson
In that same interview with Foundation, Musk says he learned a lot from another biography by Walter Isaacson: "Einstein."
As with "Franklin," this books tells the story of a genius who transforms the world with his intelligence and ambition.
As the jacket copy breathlessly proclaims, the book "explores how an imaginative, impertinent patent clerk -- a struggling father in a difficult marriage who couldn't get a teaching job or a doctorate -- became the mind-reader of the creator of the cosmos."
5. Structures: Or Why Things Don't Fall Down, by J.E. Gordon
Musk is a committed autodidact, devouring the subjects he needs to know about.
When he decided to start SpaceX, he needed to learn the basics of rocket science.
One of the books that helped him was Structures: Or Why Things Don't Fall Down, a popular take on structural engineering by J.E. Gordon, a British material scientist.
"It is really, really good if you want a primer on structural design," Musk said in an interview with KCRW.
6. Ignition!: An Informal History of Liquid Rocket Propellants, by John D. Clark
"Ignition!" is another hard-to-get-your-hands-on account of early rocket science.
"There is a good book on rocket stuff called Ignition! by John Clark that's a really fun one," Musk said in an interview.
Clark was an American chemist active in the development of rocket fuels back in the 1960s and 1970s, and the book is an account of the growth of the field and a primer of how the science works.
Though the book is hard to track down, people love it. Consider this Amazon review:
This book has the right mix of technical details, descriptions of experiments with spectacular results, background info about the why's and how's, and about the politics involved. It is a very engaging and uplifting book because Clark captured a lot of the enthusiasm he had for rockets.
7. Superintelligence: Paths, Dangers, Strategies, by Nick Bostrom
Given his leadership roles at SpaceX, SolarCity, and Tesla, Musk has had a bird's-eye view of the advance of technology.
It's not all good news.
"We need to be super careful with AI," he tweeted, because it's "potentially more dangerous than nukes."
To find out why, he says it's "worth reading" Nick Bostrom's Superintelligence, a book that makes the daring inquiry into what would happen if computational intelligence surpassed human intelligence.
8. Zero to One: Notes on Startups, or How to Build the Future, by Peter Thiel
Back in the early 2000s, when Musk was running the payments startup X.com, he was in direct competition with PayPal, co-founded by Peter Thiel, a man who's now a billionaire investor.
So when Thiel came out with his book of startup philosophy, Musk naturally endorsed it.
"Peter Thiel has built multiple breakthrough companies, and Zero to One shows how," Musk says.
The book is full of Thiel's combative insights -- like the idea that Silicon Valley's obsession with disruption is totally misguided.
9. Howard Hughes: His Life and Madness, by Donald L. Barlett and James B. Steele
In an interview with CNN, Musk said he had just finished Barlett and Steele's Howard Hughes, a biography of the eccentric filmmaker and aviation tycoon who famously got a little nutty at the end of his life.
10. Merchants of Doubt, by Naomi Orestes and Erik M. Conway
Now a documentary, Merchants of Doubt is written by two historians of science who make the case that scientists with political and industry connections have obscured the facts surrounding a series of public-health issues.
Musk recommended the book in 2013, at a D11 conference.
Around the same time, he summarized the book's key takeaway in a tweet: "Same who tried to deny smoking deaths r denying climate change."
11. The Foundation trilogy, by Isaac Asimov
It's possible that Musk's interest in space exploration technology stems from his days reading science fiction.
In a 2013 interview with The Guardian, Musk said he was influenced by Asimov's Foundation series, which centers on the fall of the Galactic Empire.
Here's what he said the book taught him:
"The lessons of history would suggest that civilizations move in cycles. You can track that back quite far -- the Babylonians, the Sumerians, followed by the Egyptians, the Romans, China. We're obviously in a very upward cycle right now and hopefully that remains the case. But it may not. There could be some series of events that cause that technology level to decline. Given that this is the first time in 4.5 billion years where it's been possible for humanity to extend life beyond Earth, it seems like we'd be wise to act while the window was open and not count on the fact it will be open a long time."
12. The Moon Is a Harsh Mistress, by Robert Heinlein
This award-winning science-fiction novel, originally published in 1966, paints the picture of a dystopia not too far in the future. It's exactly the kind of vivid fantasy world that would satisfy an active imagination like Musk's.
In the book, a group of people have been exiled from earth to the moon, where they have created a libertarian society. In the year 2076, a group of rebels including a supercomputer named Mike and a one-armed computer technician leads the lunar colony's revolution against its earthbound rulers.
It is, Musk said in an interview at MIT's Aero/Astro Centennial, Heinlein's best work.
13. The Culture series by Iain M. Banks
Musk has been plowing his way through this series since 2014.
The books tell the story of a semi-anarchist future society called the Culture, which includes humanoids, aliens, and artificial intelligences.
It's a "[c]ompelling picture of a grand, semi-utopian galactic future," Musk tweeted. "Hopefully not too optimistic about AI."
14. Our Final Invention, by James Barrat
Musk has openly warned against the dangers of artificial intelligence.
In a 2014 interview at MIT's AeroAstro Centennial Symposium, he called AI "our greatest existential threat." He's also invested in the AI firm DeepMind "just to keep an eye on what's going on with artificial intelligence."
So it's no surprise that he labeled Our Final Invention "worth reading" in a tweet. Barrat takes a close look at the potential future of AI, weighing the advantages and disadvantages.
As Barrat says on his website, the book is at least partly "about AI's catastrophic downside, one you'll never hear about from Google, Apple, IBM, and DARPA."