 Preface  xiii
contributing authors for their many important contributions to our field and for their 
dedication and patience in seeing this fourth edition come to fruition.
Finally, we thank the team at The Guilford Press who have shepherded the Hand -
book  for three decades and made sure it always had a stable home. We are grateful for 
their many contributions to make this fourth edition a reality. We particularly thank 
Editor-in-Chief Seymour Weingarten, who knew the world was ready for the next edi -
tion before we were quite ready to tackle that challenge and provided input and support 
all along the way, as well as Carolyn Graham, Katherine Lieber, and Jeannie Tang for 
their thoughtful and patient work.
Oliver  P. J Ohn, PhD  
richard  W. rObins, PhD