Lots and lots of inside stuff on what the author, an investigative journalist, sees as a unified, Soviet-sponsored network of terrorism stretching from Havana to Iran. But, she writes, the small, tightly sealed cells are beginning to disintegrate as members lose faith in murder, massacre, and kidnapping. Says one jailed fanatic: ""I realized that we were working to force the state into becoming ever more repressive."" She lays out the ostensible workings of Red terrorists on four continents--their training, sanctuaries, modes of intelligence, overt acts, and colossal need for arms and supplies that only the Soviet Union can provide. Ironically, while the democracies are put to the test, the most lawless dictatorships are left in peace: not only is it safer to be a terrorist in a free country, it is ""ideologically more satisfying."" Here are the cold killers of Italy's Red Brigades and Front Line, the Turkish People's Liberation Army, Northern Ireland's IRA, Spain's ETA-Militar, and the Popular Front for the Liberation of Palestine--more than 140 bands from nearly 50 countries or disputed territories, all supposedly linked and helping each other though not under central command. With stories of individual terrorists by the gross, the book provides tingling, cautionary reading--if hardly conclusive evidence on any score.