Product Zeitgeist Fit: A Cheat Code for Spotting and Building the Next Big Thing - Andreessen Horowitz
It's a Silicon Valley truism that product-market fit matters most for a startup. A founder's ability to achieve that elusive goal is what separates the mega-donkey-deca-unicorn success stories from the vast majority of startups that either die quick and sudden deaths or peter out slowly, unnoticed.