After two solid years of fame and fortune, Iron Butterfly were rapidly losing ground in the rock and roll sweepstakes. The band had been unable to sustain the massive success of their 1968 sophomore offering, the legendary In-A-Gadda-Da-Vida, despite releasing the rock solid Ball in 1969.

In 1970, Iron Butterfly issued a stop-gap live album that, of course, featured another lengthy rendition of "In-A-Gadda-Da-Vida," a move which hinted at a lack of direction. Countless bands had followed Cream and Jimi Hendrix down the hard and heavy path, with Iron Butterfly among the first to venture there. For whatever reason, however, they were unable to capitalize on the preferred heaviness of the era.

Just a few months following the release of Live, however, Iron Butterfly burst forth with a new LP titled Metamorphosis on Aug. 13, 1970. In keeping with the title, this project found Iron Butterfly trying to re-invent themselves. Perhaps more to the point, the band was concentrating on fine tuning their own strengths.

Metamorphosis begins with a short atmospheric piece, "Free Flight," which is really just a lead in to the driving "New Day" – not only a perfect album opener, but a mission statement of sorts for the band at this juncture. "Shady Lady" is a fairly lame, somewhat funky number that's best left forgotten at this point. A quick rebound comes in the form of "Best Years Of Our Lives," with its kick ass guitar and keyboard workouts.

Listen to Iron Butterfly's 'New Day'

"Slower Than Guns," a beautiful acoustic-based ballad focusing ecological perils, is very much of its time and place – yet listening to it decades years later, Iron Butterfly's theme still rings true, both lyrically and musically. Ditto for "Soldier on the Town." Meanwhile, "Stone Believer" is a heavy groover that, like much of Iron Butterfly catalog, deserved a better fate than being a forgotten album track.

Iron Butterfly wraps up things with another lengthy workout in the form of "Butterfly Bleu," a song that gets into all sorts of dynamics along its nearly 15 minute path before turning into gimmicks and nonsense. Eventually, the track rebounds from these meanderings, but by then it's too late.

Metamorphosis became the band's fourth straight Top 20 album, but remains the last to do so. It was, alas, no In-A-Gadda-Da-Vida – a complaint that forever hung around Iron Butterfly's collective neck.