Cay Horstmann grew up in Northern Germany and attended the in , a harbor town at the Baltic sea. He received a M.S. in computer science from , and a Ph.D. in mathematics from the in Ann Arbor. For four years, he was VP and CTO of an Internet startup that went from 3 people in a tiny office to a public company. He now teaches computer science at . Cay also writes books and articles on programming languages and computer science education.