In 2009, a glassblowing artist and former computer scientist in St. Louis named Jim McKelvey lost a sale because he couldn’t accept American Express cards. Frustrated by how difficult and expensive it was to take credit card payments, Jim set out to find a solution for small merchants like himself. He co-founded Square with Jack Dorsey in 2009 and together they reimagined the payment processing industry by turning a mobile phone into a credit card reader. In our conversation, Jim shares how Square survived the competitive threat from Amazon, the innovation stack that enabled their survival, and how we are thinking about innovation all wrong. His new book, The Innovation Stack, is available now.