The author of New Ways of War surveys the history of weapons and tactics as it relates to the histories of wars and conquests. He maintains that there are no unchanging principles, simply tendencies within periods, which repeat themselves in New forms, --such tendencies as mobility, hitting power, protection. He turns back the pages of history to 1066, when chivalry (in armor) conquered England. The pattern of development is complicated by fortifications and transport developments, by political and economic factors. The decisive weapon may achieve victory -- as the machine gun did in 1914-18; as tanks and planes will in this war, operated under the new infiltration principle of tactics. Spain was the proving ground; new defensive tactics and guerilla warfare are vital elements in the overall picture. A book for armchair strategists -- and for professionals who need to recognize the inevitability of change.