Founder and investor Elad Gil has a new book that aims to help startups with their later-stage challenges — before they get to that point Serial entrepreneur and angel investor Elad Gil has become renowned in Silicon Valley startup circles, largely because he not only funds startups but he advises many, too. Some of the tech companies he has logged time with include Airbnb, Twitter, Google, Instacart, Coinbase, Stripe, and Square.