Chicago has become to pop rock what the Woody Herman orchestra has always been to jazz: a durable, flexible outfit that incorporates new sounds without ever losing the distinctive characteristics that made it work in the first place. Certainly the fact that seven of the eight band members have been with the group since its inception in 1968 is an achievement in itself. Chicago's sound works best when its trademark brass section—still bright and snappy, thanks largely to Jimmy Pankow's arrangements—riffs up against a variety of rhythm backgrounds. Producer David Foster and three others are credited with "synthesizer programming," which adds an electronic sort of vigor to such tracks as Along Comes a Woman and Prima Donna, a tune from the Two of a Kind sound track that Chicagoan Peter Cetera wrote with Mark Goldenberg. The band's lyrics have never bowled over anyone with their profundity, and that hasn't changed. We Can Stop the Hurtin', for instance, is an anti-poverty ditty: "Families livin' in their cars and kids run numbers out of bars/Knowin' pride won't pay the bills, men work jobs beneath their skills." And Stay the Night says, "I want you to know one thing is certain/I surely love your company/And I won't take no if that's your answer/At least that's my philosophy." That's okay, guys: if we want insight, we'll go to Kierkegaard. (Warner Bros.).