Twice a year in the heart of Silicon Valley, a small investment firm called Y Combinator selects an elite group of young entrepreneurs from around the world for three months of intense work and instruction. Their brand-new two- or three-person start-ups are given a seemingly impossible challenge: to turn a raw idea into a viable business, fast.
 
Each YC session culminates in a demo day, when investors and venture capitalists flock to hear pitches from the new graduates. Any one of them might turn out to be the next Dropbox (class of 2007, now valued at $5 billion) or Airbnb (2009, $1.3 billion).
 
Randall Stross is the first journalist to have fly-on-the-wall access to Y Combinator. He tells the full story of how Paul Graham started this ultra exclusive institution, how it chooses among hundreds of aspiring Mark Zuckerbergs, and how it teaches them to go from concept to profitability in record time.