Not a single false note or fussy curlicue mars this breathtaking, true-crime-style reconstruction of a (fictional) series of 1890s poisonings within an odd extended family in the London suburbs. In two houses about a mile apart--both of them white elephants--lives the toy-merchant Mortimer clan. In ""Albert House"": fierce matriarch Harriet, her unmarried daughter, and her wormy nephew. In ""Victoria Villa"": son George (with beauteous wife Isabel) and daughter Beatrice (with hubby Roger and stepson Paul). The tense bonhomie and domestic claustrophobia are quickly colored in--through Symons' clipped narrative and Paul's intense diary--and Roger, brains of the family firm, is the first to die: a long, horrible arsenic death overseen by the fatuous family doctor. This is passed off as ""gastric fever"" till mother Harriet dies likewise. And by then, the police have a suspect--George's bride Isabel, whose erotic love letters to the late Roger have, despite Paul's Galahad-ish efforts, been exposed by a blackmailing servant. Adulteress Isabel is sure to hang, no matter how slim the evidence, unless. . . . Paul sees the truth--you may too, since Symons plays very fair--and takes the law into his own hands. So there's still more arsenic ahead as this convincing death-arama retreats into darkness. A Symons triumph of a different sort.