Since the signing of the 1998 Good Friday Agreement, the peace process in Northern Ireland has been in almost perpetual crisis. Unionists have demanded that the IRA destroy all its weapons as a precondition to power sharing. The IRA sees giving in to such a demand as tantamount to admitting defeat. The result has been a frustrating political stalemate. English's balanced and complex account of the IRA, more particularly the Provisional IRA, will help anyone understand the strong feelings and difficult issues behind today's headlines. English (Ernie O'Malley: IRA Intellectual) emphasizes that the IRA has "courageously shifted ground" by accepting the concept of consent (i.e., that the island of Ireland won't be unified without the consent of the people of Northern Ireland), rather than continuing to pursue the violent reunification of Ireland. Indeed, English stresses, the Good Friday Agreement has split the IRA just as the 1922 treaty partitioning Ireland did. The author, a professor of politics at Queen's University in Belfast, makes some controversial assertions, as when he claims that the IRA's post-1969 violence, ostensibly aimed at protecting Catholics, only led to increased anti-Catholic carnage. Even more controversially, English calls into question the whole point of the long IRA war. What English does brilliantly is to describe the IRA's own justifications for its war against Britain, with special attention to the socialism pervading much IRA belief. He has written a provocative and essential book for anyone trying to understand Northern Ireland's tempestuous recent history, providing even better insight into the IRA's ideology than Ed Moloney's recent A Secret History of the IRA. Illus., maps not seen by PW. (Aug.)