Jonathan Letham's newest novel, the sleek and effective You Don't Love Me Yet (Doubleday), is being billed as a light romantic comedy and, one gathers from the marketing, as some sort of relief from his supposedly heavier and more idea-laden successes Motherless Brooklyn and The Fortress of Solitude. But while Lethem has deftly built this novel for speed, it has a streak of darkness that proves powerfully compelling—and with no lack of ideas, either. It's set in Los Angeles (apparently in decades past—if the main character's Datsun and everyone's total lack of cell phones are any indication), among a group of melancholy, slackerish indie rock musicians and art hangers-on. It features some of the better sex and rock 'n' roll scenes in recent American literature and insinuatingly gets inside the heads of some fascinating people, most notably Lucinda, the bassist in the band and a classic young person seeking meaning in a cold and stylishly unreceptive world. Los Angeles is the city of noir, and this is a witty and entertaining noir journey into the psychological landscape of creative and lonely people in a late-20th-century American city, seething with desire and permeated with a lovely, inevitable regret.