Way back in 1985, before the CD revolution truly kicked in, Atlantic released the monumental archival project Atlantic Rhythm & Blues: 1947-1974, a seven-volume set of double-albums chronicling the label's crucial role in the development of R&B and soul. Over the course of that set (later condensed to eight CDs) it was possible to hear the music develop from blues into a soul -- an impressive feat as a sheer compilation, one that is even more stunning when it's considered that it all came from one label and its subsidiaries. Atlantic Rhythm & Blues did the job so well that the 2007s set Atlantic Soul: 1959-1975 can't help but pale a little in comparison, as it lacks both the scope and historical heft of its predecessor. Then again, Atlantic Soul doesn't try to supplant Atlantic Rhythm & Blues -- as produced and compiled by Billy Vera, it's intended as a supplement, a way to expand upon the story, fill in a few holes, explore hidden byways left behind by the first set. It's for collectors and fanatics, which should be evident by the very fact that it's released as a limited edition on Rhino Handmade, not a full-fledged release from the boutique imprint's parent label. That very audience should find Atlantic Soul enormously satisfying, although they may still have a few quibbles with some of the details. Some might find the opening triptych from Ray Charles, LaVern Baker & Jimmy Ricks, and Ben E. King to be a shade too heavy on strings, jazz and big bands -- music that sets the stage for '60s soul, yet not quite belonging to it -- some might find this too heavy on covers (albeit good, interesting ones) of pop hits by soul bands, but most will likely wonder why such staples as Otis' "Hard to Handle" and Aretha's "I Say a Little Prayer," King Floyd's "Groove Me," and the Persuaders' "Thin Line Between Love and Hate" are here, as they don't quite fit among the obscure gems that comprise the heart of this set. Such complaints are valid but they're hard to level against a set that offers so much wonderful music, so much of it unfamiliar even to dedicated soul fans. Of course, there are familiar names here -- the Isley Brothers, Don Covay, Wilson Pickett, Clarence Carter, Solomon Burke, Patti LaBelle & the Bluebelles all pop up, often repeatedly -- but Vera picks some of the best unheard sides, pairs them with them cult classics (Mack Rice, Willie Tee, Tommy Hunt, James Carr, Howard Tate), plus some complete unknowns (The Valentinos, C & the Shells, the Ohio Untouchables) and has the generosity to rightly bring in Hall & Oates' "She's Gone" as one of the great soul singles of the '70s. It all adds up to a thoroughly entertaining, enlightening set that may not be as essential to a wide audience as Atlantic Rhythm & Blues, but for anybody who's mesmorized that set, this is a welcome belated sequel.