I am indebted to many individuals for their generous assistance, especially John Davis, M.D., for helpful discussions, and Rea Wilmshurst, C. A. Silber, Burton H. Brody, and Robert Brewer for critical readings of the manuscript. I also thank my editors Robert Wyatt and Iris Bass for their enormous skill and excellent advice, Ida Giragossian for suggesting I give them a try, and Annette Johnson and Susan Abramowitz for their selfless efforts on my behalf. And, as always, my wife Karen for her unflagging support of everything I have ever done.