Motown’s golden decade—over 100 US Top Ten hits in the Sixties—was as steady and profitable as the Detroit auto plant conveyor belts that ran close to Hitsville—and, some may say, as predictable. While Memphis rivals Stax attracted the plaudits for their authentic sound, usually the product of their primitive recording environment, Berry Gordy built a studio base that could produce a slick and saleable brand of soul that appealed to both black and white audiences. Yet even Motown had the occasional surprise to throw into the mix.

In 1969, Gordy’s company decided to take a ride on the progressive rock bandwagon and launched a new subsidiary label called Rare Earth. When they signed a local band called the Sunliners to join the roster, the group swiftly switched names and actually became Rare Earth. They quickly set out their stall—soul music wrapped in a rock coating and with “Get Ready”, Smokey Robinson’s tune which provided a hit for the Temptations, extended to a whole album side, they indicated that the three minute black pop formula was not really their thing.

Thirty years on, “Get Ready” at well over 20 minutes, provides a rousing snapshot of the group in action, opening up their Best of…, one of a sequence of re-issues in a 20th Century Masters series. The performance recalls the progressive excesses of the period, more Cream or Iron Butterfly than Norman Whitfield symphony. Yet the musicianship is sharp and the vocal delivery gutsy even if the thought of one rock arrangement engaging the attention for that long now seems quaint and vaguely disagreeable.

The other songs gathered here are largely more manageable morsels with tracks like “I Just Want to Celebrate” and “Born to Wander”, both singles that even turned up on Motown greatest hits sets in the early Seventies. Covers of “(I Know) I’m Losing You”, another Tempts’ number, and the Ray Charles standard “What’d I Say” fare less well and raise questions about the viability of the rock-soul crossover. “Hey Big Brother”, however, sounds fine, a slice so reminiscent of Sylvester Stewart that you have to check you haven’t slipped on a Family Stone collection instead.

The sleeve notes point out that Rare Earth are not a forgotten combo—NWA and Beck have sampled the band, Ford have utilised their work in an ad campaign and the movie Three Kings featured snippets of one of the hits included here—yet it is hard not to categorise them as anything but a period piece. Black and white music may share a bed more often these days—think of rapcore—but those early collaborations tended to reveal the shortcomings of such a generic marriage rather than its potential.