The killing of soldiers and sailors by men fighting on the same side is an accidental hazard as old as warfare itself, but for obvious reasons those responsible for such incidents invariably take every possible precaution to see that they are kept quiet about. It has therefore been uncommon in the past to come across too many references to what is now somewhat ironically known as 'friendly fire' in works of military history. But since wars are now fought before a worldwide audience, such secrecy is no longer possible and the subject became a matter of heated debate at the time ofthe GulfWar. Helped by the growing pressure on govemments to release hitheno classified documents, Paul Kemp has uncovered over a hundred incidents of engagements between ships, submarines and aircraft on the same side in the Second W orld War. This is the first time that all the information contained herein has been gathered together in a single volume, the author having drawn upon naval archives now available in Britain, France, Italy, the United States, Russia and Japan. Much of the materia l in the book has not hitherto been published anywhere. Paul Kemp examines the most imponant of these incidents in detail and, if the result is sometimes depressing, it cannot be denied that he has produced a record of great imponance of a hitheno deliberately hidden aspect of modem warfare.