He went to the Palo Alto public library to read about rocket engineering and started calling experts, asking to borrow their old engine manuals. At a gathering of PayPal alumni in Las Vegas, he sat in a cabana by the pool reading a tattered manual for a Russian rocket engine. When one of the alums, Mark Woolway, asked him what he planned to do next, Musk answered, Im going to colonize Mars. My mission in life is to make mankind a multiplanetary civilization. Woolways reaction was unsurprising. Dude, youre bananas.

Elon Musk by Walter Isaacson