Jailbreak was such a peak that it was inevitable that its follow-up would fall short in some fashion and Johnny the Fox, delivered the same year as its predecessor, did indeed pale in comparison. What's interesting about Johnny the Fox is that it's interesting, hardly a rote repetition of Jailbreak but instead an odd, fitfully successful evolution forward. All the same strengths are still here – the band still sounds as thunderous as a force of nature, Phil Lynott's writing is still graced with elegant turns of phrase, his singing is still soulful and seductive – but the group ramped up the inherent drama in Lynott's songs by pushing them toward an odd, half-baked concept album. There may be a story within Johnny the Fox – characters are introduced and brought back, at the very least – but it's impossible to tell. If the album only had an undercooked narrative and immediate songs, such digressions would be excusable, but the music is also a bit elliptical in spots, sometimes sounding theatrical, sometimes relying on narration.

Leading his own bands in the late '70s and early '80s, Ian Gillan continued to embrace music that, not surprisingly, was heavily influenced by his former band, Deep Purple. And he never sounded more Purple-ish than he does on Mr. Universe, which isn't quite on a par with Purple's Burn but is stronger than many of the albums the outfit had recorded after Gillan's departure (some of which were quite disappointing). This is Gillan at his most aggressive and passionately rockin'. Those with fond memories of his work with Purple will appreciate the testosterone-driven energy of "Vengeance," "Roller," and "Message in a Bottle." Headbangers shouldn't overlook this one.

After working with two monstrously loud guitar heroes, Leigh Stephens and Randy Holden, Blue Cheer wanted to pursue a more subtle musical direction, and on their fourth album, simply titled Blue Cheer, they followed the path of the first half of 1969's New! Improved! Blue Cheer, featuring guitarist Bruce Stephens and keyboard man Ralph Burns Kellogg, instead of the power trio format they pioneered on their first two albums and the second half of New! Improved! with Holden.

The soundtrack to David Lynch's brilliant Lost Highway highlights the evocative gothic nightmares of producer Trent Reznor, whose Nine Inch Nails contribute the single "The Perfect Drug." Along with material from longtime Lynch collaborator Angelo Badalamenti, the set also includes new music from the Smashing Pumpkins, Marilyn Manson and Lou Reed, who offers a taut cover of the Doc Pomus classic "This Magic Moment."

Guitarist Leigh Stephens quit Blue Cheer after touring in support of their second album, Outsideinside, but he may have been amused by the fact it took three men to replace him when the band cut their next LP. There are two different and distinct bands at work on New! Improved! Blue Cheer; on the album's first six tunes, founding members Dickie Peterson (bass and vocals) and Paul Whaley (drums) are joined by Bruce Stephens on guitar and Ralph Burns Kellogg on keyboards, and this lineup bears little musical resemblance to the wildly over-amped power trio that cut Vincebus Eruptum less than two years before.

1978's Northwinds, David Coverdale's second solo album after the demise of Deep Purple, is a powerful dose of blues- and R&B-influenced hard rock. This album – the final new release on Purple Records – is also a huge leap forward in quality from the previous year's White Snake, a tentative and generally cautious record. As with White Snake, Northwinds was produced by Deep Purple bassist Roger Glover and is anchored by guitarist Micky Moody and keyboardist Tim Hinckley. Bassist Alan Spenner and drummer Tony Newman comprise the rhythm section. "Keeping on Giving Me Love" is loose and funky and a blowout jam wraps it up.

Led Zeppelin's reunion for an Ahmet Ertegun tribute concert in November 2007 (pushed back a couple of weeks due to a finger injury Jimmy Page sustained during rehearsals) seemed like a spur of the moment thing – but how spontaneous could it have been if it just happened to coincide with the release of an expanded The Song Remains the Same on both CD and DVD, the debut of their catalog as digital downloads, and the new two-disc compilation Mothership as a sampler of the whole shebang? Considering this full-scale, multi-prong assault – which also included a new album by Robert Plant, after all – it was probably not all that spontaneous. Such a precise attack suits this most mythic of classic rock groups, who always benefited from an enormous sense of scale.

Recorded in Japan in July 1973, this massive, three-LP live album was available outside the United States in 1974 but held back from domestic release in the U.S. It features the same "New Santana Band" that recorded Welcome, and combines that group's jazz and spiritual influences with performances of earlier Latin rock favorites like "Oye Como Va."

When Ian Gillan was recording his solo albums in the late 1970s and early '80s, Deep Purple's influence never went away. But Gillan did make an effort to try different things, and he was at his most experimental on Clear Air Turbulence. Enjoyable, if uneven, this album illustrates Gillan's willingness to take some chances. While the singer favors an aggressive hard rock groove on "Money Lender," the jazz fusion-influenced touches of "Over the Hill," "Goodhand Liza" and the title song could lead you to believe that you'd been listening to Weather Report and Return to Forever. Had Chick Corea formed an alliance with Deep Purple, perhaps it might sound something like "Over the Hill." Heavy metal and hard rock are in short supply on this album, which employs no less than five horn players and shows that Gillan didn't want to be a headbanger 100-percent of the time.