David Flanagan graduated from the Massachusetts Institute of Technology. He is a consulting computer programmer, user interface designer and trainer. His books include X Toolkit Intrinsics Reference Manual and Motif Tools: Streamlined GUI Design and Programming with the Xmt Library.
Yukihiro Matsumoto ("Matz"), the creator of Ruby, is a professional programmer who worked for the Japanese open source company, netlab.jp. Matz is also known as one of the open source evangelists in Japan. He's released several open source products, including cmail, the emacs-based mail user agent, written entirely in emacs lisp. Ruby is his first piece of software that has become known outside of Japan.