Dan Ingalls is a computer scientist who has made pioneering innovations in object-oriented programming and computer graphics. At Xerox PARC, he codeveloped the Smalltalk programming environment with Adele Goldberg and Alan Kay. He is the principal architect of five generations of Smalltalk environments and designed the byte-coded virtual machine that made Smalltalk practical in 1976. Ingalls later conceived a Smalltalk written in itself and made portable and efficient by a Smalltalk-to-C translator, now known as the Squeak open-source Smalltalk. He also invented BitBlt, the general-purpose graphical operation that underlies most bitmap graphics systems today, as well as pop-up menus. His most recent work, the Lively Kernel and Lively Web, is a live composition and programming environment that runs entirely in a browser and can save its results and even new versions of itself as web pages. Ingalls most recently worked at Y Combinator Research on future Lively-related projects.