Rather than an ordinary film soundtrack, this might more accurately be considered an exceptional Loudon Wainwright album. A diehard Wainwright fan, director Judd Apatow explains in his liner notes that he asked the singer-songwriter to scoreKnocked Up, Apatow's first film sinceThe 40-Year-Old Virgin, only to learn that Wainwright was about to embark on his next recording project with producer Joe Henry. The resulting album features material that Wainwright had written before the film score that the director wanted to use, other cuts that are instrumental snippets in the movie but are songs with lyrics on the album, and still others that take thematic inspiration from the film.  While Wainwright so often writes lacerating and hilariously personal material, many of these songs are more like character studies, with a musical range that extends from the ragtime "So Much to Do" (one of two songs written with Henry) and the call-and-response of the chromosome ditty "X or Y" to the Brecht/Weill cabaret tinge of "Final Frontier" to the bluesy "Doin' the Math."  Among the musicians providing stellar support are guitarists Richard Thompson and Greg Leisz and keyboardists Patrick Warren and Van Dyke Parks.--Don McLeese