Bryan Costales is CTO with SL3D, Inc. in Boulder, Colorado. He has been active in system administration for over fifteen years and has been writing articles and books about computer software for over twenty years. His most notable books are C from A to Z (Prentice Hall), Unix Communications (Howard Sams), and, of course, sendmail (O'Reilly & Associates).
George Jansen is a freelance writer who has worked with Bryan Costales on several of Bryan's books. His first novel, The Jesse James Scrapbook, is published by Hilliard & Harris. His second, The Fade-away, is published by Pocol Press. He lives in the Bay Area, drives a brand new Toyota Yaris, and enjoys baseball, classic jazz, and taking long naps.
Claus Assmann is a member of the Sendmail Consortium and works for Sendmail, Inc. He is the maintainer of sendmail 8 and currently implements a new MTA (message transfer agent) named MeTA1. His main interests in computer technology are security and performance. He studied computer science at the University of Kiel in Germany, where he received his Ph.D. in 1992.
Gregory Shapiro began his professional career as a systems administrator for Worcester Polytechnic Institute (WPI) after graduating from the university in 1992. During his tenure as Senior Unix Systems Administrator, he became involved with beta testing the BIND name server, the sendmail mail transfer agent, and other Unix utilities such as emacs and screen. His involvement with sendmail grew until he became Principal Engineer at Sendmail, Inc., where he continued to support the open source version while working on Sendmail's commercial products. He later moved into the IT team as the Senior Unix Network Systems Administrator. He is now Director, Strategic Technology at Sendmail, Inc. He is also a FreeBSD committer and has served as program committee member for BSDCon 2002 and program chair for BSDCon 2003. Greg lives in California and enjoys reading science fiction and fantasy books, traveling, and seeing movies and theater productions.