Submited by James McKelvey. McKelvey is a serial entrepreneur, inventor, philanthropist and artist. He is also the cofounder of Square, a merchant services aggregator and mobile payment company based in San Francisco, California.

In his book The Innovation Stack, he recounts how he and his cofounder, Jack Dorsey of Twitter, approached the problem of credit cards with a new perspective. The irreverent first-person narrative is an insider’s view of the world of entrepreneurship and a call to action for all of us to find the entrepreneur within ourselves—one crazy idea at a time. 

Here, he explains what an Innovation Stack is, plus what makes a real entrepreneur. 

Let’s begin with an obvious question: How does a glassblower become the founder of a major payments company?

When I lost a glass sale because I couldn’t take the customer’s credit card, I looked at the iPhone in my hand and wondered why I could take pictures and read the news but couldn’t take a credit-card payment. I love solving problems, so I called up my buddy Jack Dorsey and proposed solving this one together.