Dave Kosiur, PhD, is a networking consultant and freelance writer whose articles on WANs, ATM, IP networking, cryptography, ecommerce, and email have appeared in PC Week, Sunworld Online, and Internet Computing. He is also the author of several books, including How Local Area Networks Work and Understanding Electronic Commerce. The first edition of his bestselling The Macworld Networking Bible received the 1992 Society for Technical Communication Award of Excellence, while the Second Edition received the Computer Press Association Book Award.