When history comes to assess the present era of Silicon Valley, several chapters will be dedicated to Y Combinator.

A start-up investment and training programme masterminded by former entrepreneur Paul Graham, Y Combinator appeared at just the right moment: in 2005, when social media were emerging, the cost of launching an internet company was falling and investors’ appetite for risk was returning.

In 2000, Randall Stross, a New York Times columnist and business professor at San Jose State University, published eBoys, an account of one of the first dotcom boom’s signature investment firms, Benchmark Capital. Now he is the first author to sit in on a Y Combinator “session” for the full three months, chronicling Graham’s hard-worn start-up wisdom and the highs and lows of life as a novice entrepreneur.