'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 reported in 2009 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 Musk's vision of his future self.
"The heroes of the books I read always felt a duty to save the world," he told The New Yorker.
For those who've already read the books and seen the movies but are still hurting for more Middle Earth, Amazon officially announced it's making a "Lord of the Rings" TV series.
'The Hitchhiker's Guide to the Galaxy' by Douglas Adams
In this comedic sci-fi book, a supercomputer finds the "answer" to a meaningful life — it's the number 42.
To Musk, who read this book as a young teenager in South Africa, the book was instrumental to his thinking.
Musk was so enamored with the text, in fact, that when he launched his Tesla roadster into space, he put the words "Don't Panic!" on the car's center screen.
Those words graced the cover of some early editions of the book.
When asked in a 2015 interview about his favorite spaceship from science fiction, he said, "I'd have to say that would be the one in 'The Hitchhiker's Guide to the Galaxy' that's powered by the improbability drive."
'Benjamin Franklin: An American Life' by Walter Isaacson
Musk has called Benjamin Franklin "one of his heroes," in multiple interviews.
Franklin was one of the US' founding fathers and an accomplished inventor.
He was one of the first to prove that lightning is indeed electricity in his famous kite experiment, which led to the invention of the lightning rod. Franklin is also credited with the invention of bifocals, which are glasses comprised of two distinct optical lenses.
In this biography of Franklin, "you can see how he was an entrepreneur," Musk said in an interview with Foundation, a platform for nonprofits working on climate change issues. "He was an entrepreneur. He started from nothing. He was just a runaway kid."
He added: "Franklin's pretty awesome."
'Structures: Or Why Things Don't Fall Down' by J.E. Gordon
When Musk decided to start SpaceX, he was coming from a coding background. But he took it upon himself to learn the fundamentals 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.
Owing to his interest in rocket mechanics, Musk intimately got involved with the planning and design of SpaceX's Falcon Heavy rocket. He has served as the chief designer at SpaceX along with his CEO duties.
"The reason I ended up being the chief engineer or chief designer [at SpaceX] was not because I wanted to, it's because I couldn't hire anyone; nobody good would join," Musk said during a 2017 talk about how he plans to colonize Mars.
'Ignition!: An Informal History of Liquid Rocket Propellants' by John D. Clark
In Musk's quest to learn and master complicated subjects on his own, "Ignition!" was crucial in helping him get a handle on rockets, he said.
John D. Clark, the author, was an American chemist who was active in the development of rocket fuels in the 1960s and 1970s. The book is an account of the growth of the field and an explanation of how the science works.
Musk took the book's lesson to heart when he was working on SpaceX's Falcon Heavy rocket system. SpaceX used cryogenically cooled RP-1, a type of kerosene used in jets, and liquid oxygen to combust the fuel used to launch the rocket.
While the book is hard to find, it's available online here.
'Superintelligence: Paths, Dangers, Strategies' by Nick Bostrom
Musk has repeatedly warned against the dangers of unchecked artificial intelligence.
"We need to be super careful with AI," he tweeted in 2014, saying it's "potentially more dangerous than nukes."
In a documentary about artificial intelligence, called "Do You Trust This Computer?", Musk said nefarious companies could use AI to create an "immortal dictator from which we could never escape."
He added: "We are rapidly heading towards digital superintelligence that far exceeds any human. I think it's very obvious."
To find out why these risks are so scary, Musk says it's worth reading Nick Bostrom's "Superintelligence." The book makes the daring inquiry into what would happen if computational intelligence surpassed human intelligence.
'Our Final Invention' by James Barrat
"Our Final Invention" is yet another ode to the dangers of artificial intelligence. Musk called the book a "worthy read" in a 2014 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."
Musk agrees.
"AI doesn't have to be evil to destroy humanity — if AI has a goal and humanity just happens in the way, it will destroy humanity as a matter of course without even thinking about it, no hard feelings," he said in a documentary about artificial intelligence.
'Merchants of Doubt' by Naomi Orestes and Erik M. Conway
"Merchants of Doubt" — which is now also a documentary — was written by two historians of science.
They make the case that scientists with political and industry connections have obscured the facts surrounding a series of public-health issues including tobacco, pesticide use, and holes in the ozone layer.
Musk first recommended the book at a conference in 2013.
He referenced the book's key takeaway in a tweet, saying that the same forces that denied how smoking causes cancer are now denying the danger of climate change.
The 'Foundation' trilogy by Isaac Asimov
In addition to the "Lord of the Rings" books, Musk's early interest in science fiction and fantasy also led him to Isaac Asimov's "Foundation" series.
The books center on the fall of the fictional Galactic Empire, which consists of millions of planets settled by humans across the Milky Way Galaxy. The stories may have had a huge influence on Musk's future career trajectory.
Here's what he said about the series in a 2013 interview with The Guardian:
"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."
'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 has 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 Earth-bound rulers.
The novel is, Musk said in an interview at MIT's Aero/Astro Centennial, Heinlein's best work.
'Life 3.0: Being Human in the Age of Artificial Intelligence' by Max Tegmark
If you're sensing a common theme among the books on this list, Musk is really into exploring the future of artificial intelligence.
In this work, MIT professor Max Tegmark writes about how to keep artificial intelligence beneficial for human life and ensure technological progress remains aligned with humanity's goals for the future.
It's one of the few books Musk recommends that deals with the possibility of AI being used as a force for good in the world, rather than evil.