A bomb in a London bus sets the stage for this satisfyingly complex, wheels-within-wheels tale of IRA thrust and counterthrust, by the author of Major Enquiry (1976) and Cage Until Tame (1972). Commander James Shenton's Anti-Terrorist Squad doesn't think the bomb is officially the work of the IRA, who don't usually attack working-class people. It seems more likely that the late Dennis Baldly, the man sitting closest to the bomb, set it off inadvertently after snitching the gelignite from the IRA. When Baldry is linked to mercenary recruiter Castle, disagreements about how to handle the link--should the police put pressure on Castle or leave him in place?--foreshadow a plot in which official allies on both sides repeatedly cross each other out of territorial jealousy or tragic ignorance. First a domestic murder next door to IRA widow Maureen Driscoll brings the police to Maureen's door; then infiltrator Danny Malloy, sent to a storehouse of weapons, hears next day that an unrelated inspection has blown up the house, and his cover. When Maureen is raped by bullying Brendan Casey, who's convinced she's working with Malloy and the police, she kills him--unknowingly unleashing his current hit squad leaderless on a block of flats--and then, finding herself on the run from both the police and Casey's IRA colleagues, defends herself in a letter to Prove Council chief Little Pat McGlynn that will make heads roll and ruin a long-planned police operation against a high-placed IRA official. Henderson's world is so driven by happenstance that its chaotic violence would be funny if it weren't terrible. Fans who miss the mordant Martin Beck procedurals of Maj Sjowall and Per Wahloo are in for a treat.