The longevity of the IRA is unique among 20th century nationalist liberation movements. Its tactics -- guerrilla warfare, shadow institutions, moral force and urban terror -- have been studied and emulated in India, Algeria, Cyprus and Latin America. Long overdue, The Secret Army is the first full-length account of ""the secret army in the service of the invisible republic"" and it is a remarkably thorough, impartial and perspicacious work -- the more so since author Bell has perforce reconstructed policies and internecine schisms from interviews. Never abandoning Michael Collins' tactics forged in the 1918-1921 war with England, the IRA re-formed after each defection (Collins', De Valera's, Costello's) to the stagnant parliamentarianism of the Irish Free State. Nurtured on the litany of ancient Saxon wrongs cherished and counted like rosary beads, the IRA never progressed beyond Jacobin radicalism and Mazzinian nationalism and never succeeded in achieving a social program until its most recent alliance with the quasi-Marxist Laborites. Bell follows its fortunes -- ""the doldrums today, the gun tomorrow,"" and back again -- through the signing of the Treaty, the Civil War, the Cosgrave Ministry, De Valera's 'apostasy' and the rise of Fianna Fail, the ""red"" thirties, the dynamite campaigns, the pathetic incursions into Ulster in the late '50's and the ""advanced rot of despair"" of the early '60's followed by rejuvenation via the Ulster Civil Rights movement and the latest (1970) schism between the purists and the Laborites. Concentrating on internal organization, strategy and ideology (or the lack of ideology) he avoids the pitfall of glamorizing the fixation by men of ""narrow vision"" on the 32-county Republic while saluting their futile and splendid endurance in the revolutionary tradition.