The mystery authors working the frigid land and seas of Alaska may never outnumber those overrunning sunny Florida, but to the exalted ranks of Sue Henry, Dana Stabenow and John Straley readers should add Simpson. The author's second Liza Romero mystery (after 2000's Crow in Stolen Colors) whisks readers into treacherous seas and among even more treacherous humans. Liza runs a droll combination freight delivery and ""book-mo-boat,"" the Salmon Eye, serving the islands south of Juneau and their isolated little communities. It's a harsh but not joyless life, in which the people who share the land learn to share their lives without sharing their secrets. The drowning of a wildlife protection agent, trouble with the whale population, a knife fight, the disappearance of a traumatized Vietnam vet and a murder or two all engage Liza's attention. Simpson offers a serviceable plot and characters that compel interest without resorting to overwrought flamboyance. Still, what she captures perfectly are the rigors of daily tasks: letting the dog out for a run, maneuvering a boat single-handedly in terrible weather, getting medical attention, surviving the cold. She also captures the great irony of people so protective of their privacy and independence being so terribly dependent on one another for survival. The settlers of this land, Simpson says, ""acquire its characteristics like camouflage. Those who cannot hide never stay."" Those who remain are well worth getting to know. (May 6) FYI: Berkley will issue a simultaneous mass-market edition ($6.50, ISBN 0-425-17944-3).