In today's world, the success or failure of a company is often attributed to its company culture. But what defines culture? That's the question Ben Horowitz sets out to answer in his new book, What You Do Is Who You Are—drawing on key lessons from history and his own experience co-founding Opsware (which sold to HP for $1.6 billion) and venture firm Andreessen Horowitz (which counts Airbnb, Lyft, and Slack in its portfolio). Ben shares the two things he looks for in founders before backing them, why culture is how people behave when you're not there, and what prison culture has to do with corporate culture. Make sure to follow Ben on social at @bhorowitz0 and @andreessenhorowitz.