The year 1972 was a peak one for glam rock, and one of the genre's most representative albums, T. Rex's The Slider, was released on July 21.

The band's frontman, Marc Bolan, made a transformation from acoustic to electric warrior in 1969 with a record called "King of the Rumbling Spires." A seed bloomed in a new direction for the mod-turned-hippie, as he left behind the fairy tale whimsy of his band's earlier worked and summoned Eddie Cochran in the spirit of rock 'n' roll.

In 1970, T. Rex put out the single "Ride a White Swan," a slice of electric folk. That song, coupled with a legendary appearance on Top of the Pops in support of the follow-up single, "Hot Love," nearly spawned a movement overnight. A little dab of glitter was applied and soon glam rock was born.

With the 1971 release of the landmark Electric Warrior album, T. Rex made the leap. It was such a huge success in the group's native U.K. that Beatlemania-like adulation led to the term "T. Rextasy." But then it all came together the next year on The Slider. From the seductive surge of "Metal Guru" to the plaintive album closer "Main Man," it's rock, pop and folk in brand new, glittery clothes.

Listen to T. Rex Perform 'Metal Guru'

"Telegram Sam" was pulled as the first single from The Slider, and it, along with the album's second single, "Metal Guru," defined T. Rex's the bump-and-grind coolness. Tony Visconti's production, Bolan's dynamic guitar and vocals, percussion by Mickey Finn and backing vocals by all helped shape the sound of the record and an era. The deep tracks work too. The title tune is a raunchy, sexy rocker, "Ballrooms of Mars" is a subtle groover and "Buick Mackane" aims for riff-rock heaven.

T. Rex are pretty much a footnote in the U.S., where "Bang a Gong (Get It On)" was their only hit. But in their homeland, they were huge. The Slider and its singles were all monster hits. It's no stretch to say that without Bolan unleashing this glitter beast, there may never have been a Ziggy Stardust, let alone the clones that followed.

Bolan would release one more classic LP, 1973's Tanx, before the glitter began to fade on his golden era.

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