Subtitled ""The Organization and Operations of the U.S. Military Establishment,"" this instructive book proceeds from the proposition that ""The military strength of the United States is the best guarantee we have for the continued existence and growth of the Free World."" Lt. Col. Powers' purpose is to give a comprehensive picture of our national defense potential ""as it actually exists,"" and his mission is accomplished. He finds the defense program ""inordinately complex and specialized,"" and offers background to form ""the basis for making sound judgments about new policies."" The hierarchies and chains of command are nearly as complicated as the hardware must be, the ""critical aspects of each function as established by the Congress and shaped by past and present Administrations"" are not easy for the layman to recognize. Neither are the shady areas where defense policies merge with or impinge upon foreign policy or economic issues. Thus, the official line, presented fully as it is here and with clarity, ought to be a pre-requisite to any intelligent discussion of ultimate objectives.