This very readable book is a study of "asymmetric" warfare; specifically, it is an examination of 18 leaders of military conflicts, each of whom acted in asymmetric / irregular or otherwise unconventional ways. Each chapter is part biography, part history lesson, and part examination of military art and science in practice. It follows several themes relevant to unconventional warfare, including moral legitimacy as a strategic goal, dividing one's forces into multiple small units to attack multiple locations simultaneously, and countertactics to such attacks. Theses themes relate many of the chapters, but most chapters can be read independent of the whole and still be enjoyable and useful lessons on history and tactics.

See more on John Arquilla here: http://en.wikipedia.org/wiki/John_Arquilla