It's hard to have a more milquetoast image than Olivia Newton-John. Even when she was decked out in stretch pants and stiletto heels at the end of Grease, you never mistook her for a wild girl. Proudly carrying the torch once held high by Karen Carpenter, Newton-John embodied the safer and, yes, blander side of the '70s and early '80s. But just like Carpenter went on to be rehabilitated as a pop singer, Newton-John's career deserves a second look--and this compilation is a good way to start. Even if the singer's precise touch was audible as early as 1973 (on the countryish "Let Me Be There"), she reached her peak five years later with Grease and the torchy "Hopelessly Devoted to You." "Physical" may be the best-known episode of the singer's leg-warmer years, but the one to cherish forever remains "Xanadu." On it, Newton-John basically fronted Electric Light Orchestra and the result is one of the most underrated songs of the past 25 years. --Elisabeth Vincentelli