Book recommendations from super smart people are always great. But what's even better is when smart people share not just whatever title happens to interest them at the moment, but the one book that changed their life the most. 

Which is just what entrepreneur and Y Combinator founder Paul Graham asked his million or so Twitter followers to share recently: 

The result was a flood of suggestions, some of dubious merit but many from top names in startups, including founders, investors, and executives. Here are some of the best and most interesting below, but I warn you, diving into this thread might cause the size of your to-read queue to explode. 

At least that's what it did for LEADx founder Kevin Kruse.

1. The Moon Is a Harsh Mistress by Robert Heinlein

To get the conversation rolling, Graham shared his own life-changing book, The Moon Is a Harsh Mistress, a classic sci-fi novel about the revolt of a lunar colony. He's far from the only business titan who claims sci-fi as a huge influence. Everyone from Elon Musk to Bill Gates has talked publicly about how sci-fi shaped their character and career. 

The novel "made me want to work on A.I., which led to Lisp [the programming language where he made his first professional mark]," Graham explains 

2. Barbarian Days: A Surfing Life by William Finnegan

Other founders preferred more outdoorsy fare. Barbarian Days, a Pulitzer prize-winning memoir by a lifelong surfer, "allowed me to understand what things might be important to me that I was not paying attention to. It took me on a journey that I eventually reproduced in my own way," said entrepreneur-turned-consultant Ramon Cacho. Other founders have also shared how surfing influenced their work in startups

3. Guns, Germs, and Steel by Jared Diamond

500 Startups founder Dave McClure doesn't explain how Guns, Germs, and Steel changed his life in his brief tweet, but it's not hard to see how a sweeping look at the hidden factors that helped the West dominate the globe could push a founder to think big and reconsider their understanding of the world. Another Pulitzer prize winner, the book "dismantles racially based theories of human history," according to Amazon. 

4. The Untethered Soul by Michael Singer 

CreativeMornings founder, designer, and blogger Tina Roth Eisenberg went the spiritual route, offering The Untethered Soul as her pick. Futurist Ray Kurzweil called it "a radiant treatise on how to succeed in life from our spiritual quest to our everyday tribulations."

5. Extreme Ownership by Jocko Willink and Leif Babin

The more down to earth founders of Copyedit Mom, Natalie Batt and Faith Hough, suggested this book by two Navy SEALs was the push that helped them move from dreaming to building. "Extreme Ownership by @jockowillink and @LeifBabin helped launch Copyedit Mom! It's like an adrenaline shot for going from idea to execution!" raved the tweet. 

6. The Upside of Stress by Kelly McGonigal 

You can imagine why someone with a career as high-octane as famed entrepreneur and investor Keith Rabois's might find The Upside of Stress, a book by a Stanford psychologist on how to transform stress into fuel for your ambitions, so life-changing. 

7. Why We Sleep by Matthew Walker 

It's also no wonder why Rabois would include this book from a leading expert in the science of sleep and why getting enough of it is so essential for the body and mind. Hopefully after reading Why We Sleep he's found time to get a little more shut eye. 

7. Anna Karenina by Leo Tolstoy 

Not all the books mentioned were about some form of personal or business transformation. Sprinkle Lab and Wrapbook co-founder Cameron Woodward cited classic Russian novel Anna Karenina as his most life-changing book. "The lesson of causation from micro choices and assumptions and delusions that have macro consequences," was his main takeaway, he explains. 

8. Surely You're Joking, Mr. Feynman by Richard Feynman

Another offbeat response came from Y Combinator partner Trevor Blackwell. Surely You're Joking, Mr. Feynman "was my first inkling that an ordinary person could go around solving physics," he tweeted about the memoir by the physicist. Feynman's brain certainly wasn't ordinary, but his background was, and he went on to win the Nobel prize. Everyday people can do incredibly things, Blackwell learned. 

9. The Dictator's Handbook by Bruce Bueno de Mesquita and Alastair Smith

Sometimes, the best way to learn is by negative example. Founder-turned-startup exec Andreas Klinger said The Dictator's Handbook, which is basically what the name implies, changed his life "because it gave me a simple game theory framework to understand political injustice."

10. A Short History of Nearly Everything by Bill Bryson

Adla founder Holly Leslie shared how her "dad got me the book when I was 6 and it really got me curious about the world around me." No wonder. A Short History of Nearly Everything is a beloved and incredibly ambitious bestseller that aims to cover everything from the Big Bang up to today.

11. Ender's Game by Orson Scott Card 

This classic sci-fi novel, which inspired the '80s movie, was a favorite of young Mark Zuckerberg. Pioneer founder and former Y Combinator partner Daniel Gross loved Ender's Game too. "Wait, the _kids_ are in charge? Not the adults?" is how he sums up his main takeaway from the book. "It gave me license to act with much more agency."

12. Zero to One by Peter Thiel 

So many founders said PayPal founder Peter Thiel's reflections on startup life changed the course of their lives. "Zero to One changed everything," wrote investor Katherine Boyle. Writer Bonnie Kavoussi, Quillette founder Claire Lehmann, and lawyer Mandar Kagade all chimed in to agree. 

What book most changed the course of your life?