Biographical Sketch: Mark Nelson, CISSP®, CSSLP™ is a Senior Software Engineer with IBM's z/OS Security Server Design and Development Team in Poughkeepsie NY, where he has spent the past 23 years working on RACF. Mark's focus with RACF has been on auditing and data analysis (IRRDBU00, IRRADU00, RACFICE), RACF's Health Checks, RACF/DB2, and RACF's support for digital certificates. Mark is an active speaker on RACF, having spoken to user groups and IBM field representatives on four continents, and has received several SHARE "Best Session" awards, four "Top Gun/Best Session" awards from the Vanguard Enterprise Security Expo, and was the 1999 recipient of the Vanguard "Chairman's Award". Mark is a co-author of the book "Mainframe Security for Security Experts: A Introduction to RACF", has helped write several Redbooks, and has published articles in NaSPA's Technical Support, z/Journal, and IBM's Hot Topics. Mark is the director of the Mid-Hudson Valley IBM Club Chorus and a private pilot.