The editors would like to express their thanks to a number of colleagues whose insights and comments contributed to the development of the book. Among those who were particularly helpful were Robert Nurick, Vic Utgoff, Mike Clarke, Jorg Baldouf, Jean Chabaud, John Roper, Edwina Moreton, Lawrence Freedman, Francois Heisbourg, and Harley Balzer. We are particularly grateful to General William Y. Smith, President of the Institute for Defense Analyses, for his intellectual encouragement.