Any edited volume is bound to be a potpourri, and this book is no exception. But it has a useful collection of pieces on how contemporary communications shape nontraditional forms of warfare. The essays include chapters on the tactics of anti-World Trade Organization protesters during the riots in Seattle in 1999; the Internet and international crime; "hacktivism" ("the convergence of hacking with activism"); and the rise of what the authors term "netwar." Before September 11, readers might have been naturally inclined to pooh-pooh such talk of loose networks of terrorists, criminals, and militant subversives. But the peculiar structure of al Qaeda vindicates much of the argument here -- as the editors point out in a postscript written shortly after the terrorist attacks.