Throughout the 19th Century, it was commonly said that "the sun never set" on the vast and mighty British Empire. And for the first half of the '70s the same was true of the globe-spanning career of Spinal Tap. So much so that the group chose to adopt this motto for their hotly anticipated eighth studio album, which arrived in stores on April 1, 1975, resplendent in the unmistakable colors of the Union Jack. However, Spinal Tap bassist Derek Smalls misheard the old saying, and the record was released as The Sun Never Sweats.

In any case, it would take a lot more than that to shake the confidence of Nigel Tufnel, his inseparable partner-in-crime and fellow frontman David St. Hubbins, and the steadfast Smalls – the three men responsible for guiding Spinal Tap to the higher echelons of Britain's ruling rock and roll aristocracy. Since the release of 1970's groundbreaking Brainhammer album, which had seen the group abandon the incense and peppermint of their psychedelic past to embrace the bulging hard rock muscle set to dominate a new decade, Spinal Tap's career had been building from strength to strength to strength.

They'd successfully discovered an entirely new and younger audience by having the foresight, guts and punctuality to undertake this daring new direction – then rode that bandwagon for all it was worth over successive LPs like 1971's Nerve Damage, '72's Blood to Let and 1974's masterpiece Intravenus de Milo. Each one of these albums spawned radio-conquering hits, led to exhausting tours that continually tested the band's stamina for groupie consumption, and filled Spinal Tap with enough confidence to steer them towards the recording of their first full-fledged concept album in The Sun Never Sweats.

It was decided to base their magnum opus on the complete and unabridged history of the British Empire. As Smalls put it, "The album was basically just saying that the empire was a good idea, that subjugating foreign peoples ... there was nothing wrong with that." But before they could embark on this ambitious undertaking, Spinal Tap's three-headed creative fulcrum (plus drummer Peter "James" Bond) secured the services of former Kilt Kids keyboard wizard Ross MacLochness, who brought his classical, Gaelic and boogie-woogie influences to bear on conceptual song-cogs like "Daze of Knights of Old," "The Princess and the Unicorn," and "The Obelisk."

Unfortunately, Spinal Tap were roasted, carved up and served with all the trimmings by critics. Even band biographer Peter Occhiogrosso dismissed The Sun Never Sweats as "a late-blooming concept album that only a Taphead could love, padded as it is with creaky period pieces, too-precious Donovan knock-offs, and twisted histories."

Watch Spinal Tap Perform 'Stonehenge'

The only songs to emerge from this era turned out to be the album's ponderously patriotic title track and the reliable and ritualistic in-concert show-stopper "Stonehenge," both of which remained staples of Spinal Tap's future tours and were later chosen for inclusion in the band's 1984 collection, Heavy Metal Memories.

Looking back, there were perhaps underlying causes behind Spinal Tap's sudden fall from grace that went beyond a few critics and sub-par tunes. After all, just one year later, punk rock would rear its spiky head, condemning long-haired giants of the '70s like Pink Floyd, Led Zeppelin and Spinal Tap to dinosaur status, bound for extinction before too long. Even more incredibly, many music buyers actually seemed to believe such outlandish claims, and soon Spinal Tap and all of their heavy-rocking brethren were fighting for their careers, their lives, even their lunches.

To wit, Spinal Tap's next release of 1975, the triple-LP live concert document Jap Habit, was rudely pilloried as so much bloated hogwash. American record buyers had to make do with merely a double vinyl edition, meaning these fans were sadly deprived of the band's expanded improvisations across Far East favorites like "Saliva of the Fittest," "Nerve Damage" and "Silent but Deadly." It got worse, as Spinal Tap's ensuing attempt to relate with this brash new generation via 1976's glam-rocking Bent for the Rent went absolutely nowhere. Its poor sales caused Spinal Tap to be unceremoniously dropped by Megaphone Records.

Luckily, the tides of musical fashion soon turned yet again, away from punk and – oddly enough – toward Jap Habit's standout track "Nice 'n Stinky," which became a surprise hit in America. This proved just the shot in the arm necessary for Spinal Tap to find a new home at Polymer Records, where the unwavering support of iconic label chairman Sir Denis Eton-Hogg soon paved the way to a slow but steady comeback.

No, the members of Spinal Tap are never likely to forget the trials and tribulations that afflicted The Sun Never Sweats, but they also surely credit this criminally misunderstood masterpiece for teaching them a whole lot more about the sights, sounds and smells of a life in rock and roll.

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