Love Train: The Sound of Philadelphia, released by Sony Legacy in 2008, provided an excellent and deep overview of the Philadelphia International catalog, as well as Kenneth Gamble and Leon Huff's outside work as songwriters and producers. The 40th Anniversary Box Set, released in 2012 by the U.K. label Harmless, sticks to PIR but goes ten discs deep. Naturally, there is a significant amount of overlap; 29 of the 71 songs featured on Love Train, including every big PIR single, appear here. In addition to featuring all the popular classics -- "Me and Mrs. Jones," "Wake Up Everybody," "T.S.O.P.," "Love Is the Message," "Love Train," "Back Stabbers," "You'll Never Find Another Love Like Mine," "Only You," and on and on -- the box showcases the label's stylistic breadth. There was neither one Philly sound nor one PIR sound. Picking five songs at random from five different artists will likely demonstrate the label's range from perfectly shaped soul-pop to progressive and experimental rhythm & blues, as well as its relevance beyond the '70s. Billy Paul's rollicking and explosive take on "Compared to What" (1971), Yellow Sunshine's eponymous Santana/War-like funk-rock hybrid "Yellow Sunshine" (1973), Dexter Wansel's jazz-funk floor burner "Life on Mars" (1976), the Jones Girls' transportive "Nights Over Egypt" (1981), and Phyllis Hyman's plush "Ain't You Had Enough Love" (1986) have their own placement as significant events in the PIR time line. (One minor quibble, possibly explained by a licensing issue: Edwin Birdsong's "Cola Bottle Baby" or "Phiss-Phizz" should be here.) This is a slick black box, albeit one prone to dulled and whitened corners, with a thick booklet stuffed with photos, liner notes, and detailed track information. There are meticulous singles and albums discographies, too. It's a lavish treat for anyone with serious interest in the label, and it should manage to stun hardcore PIR fans as well. No one has done such a loving job with the entirety of the label's catalog.