The O’Jays, Harold Melvin and the Blue Notes, Teddy Pendergrass, Lou Rawls, and Patti LaBelle were among Philadelphia International Records’ most prominent stars and the songwriting / production team of Kenny Gamble and Leon Huff defined an entire era of ‘70s Soul music with their tight grooves and lush orchestration. But not everything they touched turned to immediate gold. This 16-track collection, released in 2008 to coincide with Gamble and Huff’s long deserved induction into the Rock and Roll Hall of Fame, assembles tunes that were every bit as alluring as their better-known counterparts, but for matters of promotion, timing, and other mishaps, and simple unlucky fortune, have been left to obscurity. But there’s no shortage of powerful performance here. Bunny Sigler and Dee Dee Sharp’s “Conquer the World Together” is fiery Soul. Johnny Williams’ “It’s So Wonderful” stomps with a horn menace and the same urgent vibe that sent the O’Jays’ “Back Stabbers” to the top of the charts. Some are acknowledged in their time, while others wait in obscurity to be rediscovered, their brilliance no less luminous, as this collection of obscurities bears out.