In England, rock bands often seem to crystallize around an idea, usually one that has musical and political components. Almost overnight you have a movement, replete with its own dress code, dances and ideology. The idea that launched the two-tone movement in the late 70s had to do with integration: white and black youth uniting over their working-class roots, white rock melodies with black Caribbean dance rhythms. The synthesis was an effervescent yet driving new music. As this retrospective set demonstrates, the English Beat, which broke up last year, had the best chops, material and staying power of the two-tone bands. A seven-piece ensemble, they generated a dervishlike rhythmic intensity; but what set them apart from such stylistic neighbors as the Specials were their striking melodies, their gruff, echoey sax breaks and their ability to keep the overall sound kinetic yet uncluttered. There's plenty of good music here (including eight previously unreleased, remixed or live cuts), but the lovely, lilting Doors of Your Heart and Mirror in the Bathroom, with its headlong urgency, are benchmarks. So are the Beat's creative and humorous treatments of Smokey Robinson's tune Tears of a Clown and Andy Williams' Can't Get Used to Losing You. It is both rock's strength and weakness that it is music of the moment. But in its best songs, the English Beat makes its own moment endure.