Acknowledgments With the publication of this fourth edition, our appreciation to the col- leagues, clients, family, and friends who supported us . . . quadruples! We continue to be open to learning from all of them and believe that is the way to stay current. We have grown up over the years with a wonderfully strategic and supportive publishing team at Berrett-Koehler. Its president, Steve Pier- santi, sees all, knows all, and notices all. He is superb at acknowledging precisely what we did well and pointing out (with equal precision) what we needed to improve. Jeevan, Kristen, Mike, Rick, Marina, and Tiffany