. Rex's seminal frontman Marc Bolan has been voluminously recorded, bootlegged, compiled, and distributed since the '60s, although with a disorganization unbecoming the latitudes of his contribution. Some fans would pay top dollar for a recording of the band tuning up for an hour, and there are actually precious moments of such filler on Bump 'N Grind, although it never devolves into a gossipy, novelty outtake album. Ever the contrary: Bump 'N Grind liberates a fiesta of master tapes and daring, obscure discoveries and never stoops to the barrel-scraping of many elaborate posthumous comps. This is the original monster rock, the floor-tremblers and widow-makers that were the T-Rex experience. Fans will delight in a full version of "the Groover," where Bolan impresses gods on high with his effortless vibrato, as well as an open-veined run-through of "Telegram Sam" (with surprising controversial, X-rated lyrics). An utterly awesome six-minute version of "20th Century Boy" blasts through the conventional fades with guitars emulating the coupling of unlikely machines in an utterly unnatural world. Included is the "mysteriously cancelled" (and problematic) "Christmas Bop," and as catharsis, a stunning 12-minute version of "Children of the Revolution." Here, the volatile genius (Bolan) simultaneously teaches the band the song, argues with the way-off backup singers, and obsesses with fingering Ravel's "Bolero" without cease. Bump 'N Grind is a quintessential rock & roll record in the most literal sense.