Michael Hartl is a programmer, educator, and entrepreneur. He coauthored RailsSpace, a best-selling Rails tutorial book published in 2007, and was cofounder and lead developer of Insoshi, a popular social networking platform in Ruby on Rails. Previously, he taught theoretical and computational physics at the California Institute of Technology (Caltech), where he received the Lifetime Achievement Award for Excellence in Teaching. A graduate of Harvard College, he holds a PhD in Physics from Caltech, and is an alumnus of the Y Combinator entrepreneur program.