Murder at the auction-house--as Collins (Dearest Amanda: An Executive's Advice to her Daughter) makes a faintly amateurish but tart and sprightly debut as a mystery-writer. Collins' narrator-sleuth is attractive Boston gallery-owner Helen Greene, in her early 30s, a brisk sort who's rather soggy, however, about the two main men in her life: her late father, the gallery's founder; and big-time rival Baton Morley, a 40-ish dreamboat who was once Helen's adored mentor, soon dropped her, and now still cruelly toys with her. Then, after a detailed session at a country auction-house (focusing on Helen's thwarted attempt to regain a beloved painting she once had to sell), Morley turns up dead--stabbed with an African sceptre--in a walnut chest that's about to be auctioned off. And Helen, Morley's scorned lover and auction-bidding opponent, is a top suspect. So, in predictable, implausible fashion, Helen turns detective in order to clear her own name, quizzing an array of creakily motivated suspects: dealers who were outdone by Morley, who owed him money; a fatuous, ambitious gallery-owner who sought Morley's sponsorship without success. The chief clues surface when Helen takes inventory at Morley's art-treasure-filled manse. And her chief ally is a sloppy, bearish, rich art-collector--who is destined to become her True Love from their very first meet-cute encounter at the auction. The plotting here, right up to the gothicky showdown with a semisurprising culprit, is humdrum at best--more Murder, She Wrote than Emma Lathen. The gallery/auction detail, though hard-working and lively, is often less than fully convincing. Still, Helen has her personable moments, and the supporting cast includes a true charmer or two (along with some overdone ""colorful"" types. So readers with a taste for Boston or auctions, or both, should be modesly entertained by this sedate mysterycomedy, which is intended to inaugurate a Helen Greene series.