Who is this mystery man who has donated $2.6 million to Endorse Liberty, the pro-Paul super PAC that has produced several viral videos and sponsored sharp attack ads against Santorum, Gingrich and Texas Gov. Rick Perry?
Thiel, 44, is a low-profile libertarian with a background as quirky as the candidate he supports.
Born in Germany, he's a self-made billionaire who became a chess master as a child, majored in philosophy at Stanford University, and founded the conservative-libertarian Stanford Review to "present alternate views" on a campus he felt was dominated by liberals.
... But the Bay Area billionaire is not just a free-enterprise fan. He's also a proud gay Christian who has supported a wide range of causes including gay rights, freedom of the press, antiaging research and artificial intelligence.