Plenty of rock duos, like Loggins & Messina and Seals & Crofts, have bitten the dust, but this Pennsylvania pair have lasted nearly a decade. Their R&B-derived songs are hardly innovative, but their secret weapon is the hook: a clever musical phrase that imbeds itself in the listener's brain. Almost every one of the 11 songs on this LP is an addicting melody. The catchiest of the bunch are One on One and Guessing Games. Another, Maneater, is about a woman who is the toughest customer since the dame in Billy Joel's Stiletto. "The beauty is there," Hall and Oates sing, "but beast is in the heart." The only borrowed tune included is Family Man, a funny song about a hooker and a married, reluctant hookee. Hall and Oates (the LP title plays on their initials) seem to have pulled into their duo a creative partner in the person of Sara Allen, Hall's longtime girlfriend and collaborator on five sets of lyrics. Janna Allen, Sara's younger sister, also helped write a pair of songs. Of course megasellers Hall and Oates have a great economic incentive for staying together, but the chemistry is what's vital, and they seem as well matched as hydrogen and oxygen.