As pseudonym-fanciers know, E. V. Cunningham is a sometime byline for mainstream bestseller Howard Fast. Ironically, however, it's Cunningham's Masao Masuto of the Beverly Hills Police--seen first in Samantha (1967), reappearing as a series hero in 1977--who has inspired Fast's best writing in years. And this new case, despite a rather outlandish denouement, is the top Masuto so far--beginning when a canyon-side swimming pool breaks off during heavy rains, sliding down the hill and revealing a skeleton in its exposed concrete foundation. Zen-ish, stubborn Masuto starts deducing like mad--deciding that the corpse was hidden by a workman during the 1950 house-building, that the killer was a big embezzler who needed to assume his victim's identity (with help from plastic surgery). And some of his ideas are confirmed when three people involved with that 1950 house-building are rapidly murdered. But though Masuto's reconstruction/identification process is fascinating, half of his theories turn out, refreshingly, to be all wrong. And only when he finally faces the aging but super-ruthless killer at dinner and in karate combat does the truth straighten out--with an implausibly coincidental (but undeniably creepy) connection to a Masuto relative. Fast, scary, grim yet upbeat: a real crime-treat and an especially welcome arrival from L.A., where most of the detecting these clays has become tediously down-and-dirty.