BLACK GLASSES LIKE CLARK KENT: A GI's Secret From Postwar Japan, by Terese Svoboda. (Graywolf, paper, $14.) When Svoboda's uncle Don, who had served as an M.P. at a prison in postwar Japan, died, he left behind a mystery. In taped reminiscences, he had talked about wide-scale executions of American prisoners. ''The prison was getting overcrowded,'' he had said, and a captain ''said he was going to have to start executing the prisoners, the ones in the death cells.'' Or Don may have accidentally killed a prisoner; he never mentioned the death on tape, but his brother believes it happened. After the Abu Ghraib scandal in 2004, he suffered from depression and symptoms of post-traumatic stress. ''How 'post' is post?'' Svoboda asks the Harvard psychohistorian Robert Jay Lifton. ''It's certainly not fixed in time,'' he says. ''Sixty years? It's been documented.'' Throughout the book, Svoboda, a poet and fiction writer, seems self-absorbed, describing a weight-lifting class (''I curl a bicep'') and domestic scenes. Yet ''Black Glasses Like Clark Kent'' is suspenseful, and contains a message about war that makes it worthwhile. She interviews people here and in Japan, but never determines whether her uncle knew firsthand about war crimes or imagined them. It almost doesn't matter: his depression was debilitating; he tried antidepressants and electroshock. The thing that sustained him was talking into the tape recorder, describing his nightmare. When he was done, he killed himself, another casualty of war. WINNER TAKES ALL: Steve Wynn, Kirk Kerkorian, Gary Loveman, and the Race to Own Las Vegas. by Christina Binkley. (Hyperion, $25.95.) Binkley, a columnist for The Wall Street Journal, traces the gambling industry and its hub, Las Vegas, during a time in which Vegas went from Sin City (pre-1989) to Kid Friendly (early 1990s) and, happily, back to ''cards, sex, all-night partying.'' In addition, she paints portraits of characters like Steve Wynn, with his ''Vegas style'' hair; his antique Dante volumes, their pages gutted and replaced with Styrofoam (a perfect metaphor for the new Vegas and its ersatz Paris/New York themes); and his family, which has a flair for drama. His wife, for example, describes the trauma of being forced to sell Mirage Resorts: ''It's like 9/11.'' Binkley examines the neck-chain-and-pinkie-ring set and comes up with great material (Wynn, a world-class art collector who outbids Ronald Lauder and Si Newhouse, suffers from retinal degeneration and is partly blind). Yet the author doesn't provide a coherent point of view -- or even an interesting argument. Mostly, she presents Vegas as a freak show, ''the theater of the bizarre,'' as someone describes a meeting with Wynn. The truth is that the casino mentality and aesthetic are mainstream, touted as ''economic development'' across the country. Even New York, Anthony Bourdain laments in ''Winner Takes All,'' looks increasingly ''like Las Vegas.'' The book spins along, with page after page of colorful description, but never comes together as a narrative. [ABSTRACT FROM PUBLISHER]