During 1966, Motown adopted the phrase "The Sound of Young America" as their slogan -- a claim that was not hyperbole; it was the truth. The label was a hit machine, cranking out single after single, and almost all of them were hits of some magnitude, with 22 singles reaching the pop Top 20 and a slew of others pushing up the R&B charts or skimming the lower reaches of pop. This is an astonishing success and it reflects just how tight and focused Motown had become, a trait that is reflected in the listening experience of the five-disc, 125-track box The Complete Motown Singles, Vol. 6: 1966. Every other Complete Motown Singles box prior to this -- even the heady years of 1964 and 1965 -- was studded with subsidiary detours, Berry Gordy's forays into gospel, jazz, country, and other markets. With Motown indeed turning into the sound of young America, Gordy and his crew no longer bothered with these other potentially lucrative markets and concentrated on their core strengths, almost without exception. One of those exceptions happens to be the Mynah Birds, the storied, until now unheard band featuring Rick James on vocals and Neil Young on guitar, but their unreleased single, "It's My Time"/"Go on and Cry," fit into the rubric of young America: it was a perfect blend of Beatles rock and Motown pop-soul. It, of course, was a blip on the radar, a brief moment where Gordy and Motown flirted with the idea of rock & roll. For the most part, 1966 was devoted to exuberant, exhilarating soul, ranging from the elegant Supremes to the dirty grooves of Junior Walker & the All-Stars.

What impresses most on The Complete Motown Singles, Vol. 6 is the variety and sophistication of this soul. Far from being a series of monochromatic spins on a single bouncy beat, there's a near-endless variety of sounds here. Much of it is bright, danceable, and infectious, as heard on Shorty Long's "Function at the Junction," the Temptations' "Get Ready," and Marvin Gaye & Kim Weston's "It Takes Two," but there's a wealth of lesser-known gems, from the Elgins' "Heaven Must Have Sent You" to a stack of sides from Chris Clark and Frances Nero's "Keep on Lovin' Me," a staple of Northern soul. Any Northern soul acolyte will find much to treasure here, but there's grittier, harder music here, typified by the Four Tops ("Reach Out [I'll Be There]") and the Temptations ("Ain't Too Proud to Beg," "[I Know] I'm Losing You"), who also saw Jimmy Ruffin step out with "What Becomes of the Broken Hearted." The Supremes, the Four Tops, and the Temptations were still at their peak popularity, but the year saw a few of the label's other stars in transitional mode: Smokey Robinson & the Miracles dropped off the radar and Marvin Gaye was busy dueting with Weston and Tammi Terrell (and also cutting the oddity "The Teen Beat Song," a love letter to the Detroit Free Press), while Stevie Wonder started dabbling with Bob Dylan in an excellent cover of "Blowin' in the Wind" (which is not the only acknowledgement of social upheaval; the Monitors' "Greetings [This Is Uncle Sam]" is a rare, early Vietnam protest tune). Amid this, there's the debut of the Spinners and the Isley Brothers, who had a hit with "This Old Heart of Mine (Is Weak for You)" but whose other singles prove that this was far from a one-shot wonder from them. Gladys Knight & the Pips also debuted this year with the good "Just Walk in My Shoes," but that's of a piece with the singles by the Monitors, the Originals, Robin Rick & Him -- songs that aren't well known but are nevertheless excellent and help make The Complete Motown Singles, Vol. 6 not just a necessary historical document but a virtual non-stop party. ~ Stephen Thomas Erlewine, All Music Guide