Roessner's hardcover debut--part scientific puzzler, part social projection, part mutable-reality shocker--explores an intriguing conjecture: What if 90 percent of the human race, selected utterly at random, suddenly vanished without a trace? Well, two decades after the Vanishing, what remains of California society has fragmented into a bewildering array of groups ranging from forlorn Housers (they hang around their own houses, hoping that those who vanished will somehow, someday, return) to crazy-cult Heaven Bounders (they believe that their mission is to exterminate everyone still alive). For the diverse inhabitants of a rambling, continually expanding communal structure--known simply as The House--survival is the first priority, and so children are taught survival skills as soon as they can walk. Young, thoroughly competent Renzie, however, suspects that The House may be something more than just a big, complicated dwelling--a view shared by Nesta, an aging physicist who walked all the way from Pennsylvania to join a local research group. In probing the causes of the Vanishing, Nest has accumulated evidence that it was merely a prelude to even stranger events. As the mad Bounders mass for an all-out assault on The House, Nesta and Renzie carefully observe the behavior of Minda and the younger generation of House children, who seem able to pop in and out of alternate realities at will. Thoughtfully conceived, convincingly and elegantly developed, with solid female leads and a splendid conclusion. Deeply satisfying.