Somehow, when I was twelve years old, I became fixated upon a Bob Dylan song called "The Mighty Quinn." I think my father used to sing it. For Christmas that year I received Manfred Mann's "Watch" album, in which "The Mighty Quinn" was transformed into an extended psychedelic freakout. This album, improbably, became the soundtrack to my junior highschool years.
Here is a contemporary performance by the band -- then called "Manfred Mann's Earth Band" -- showing that in many ways their songs were just excuses to jam. Check out the sublime guitar/keyboard interplay between Chris Thompson and Mr. Mann himself.
Eventually I realized that this whole "Manfred Mann" thing was much looser and stranger than I'd imagined, being a revolving door of top-flight musicians who performed around Mr. Mann and occasionally produced albums. They'd started out as an entertaining "British Beat" band (the "Do Wah Diddy Diddy" stuff), moved into R&B, then eventually became the whacked-out prog-rockers who I fell in love with. Their mystical, drug-inspired lyrics were pure magic to me as a child.
During the '80s they flirted with African rhythms and new wave -- which serious musician didn't? -- and then Mr. Mann started exploring free jazz...and eventually they moved out of my consciousness altogether. But I'll still pick up any Manfred Mann album I find, and I'll love it whether it's pop fluff like "Pretty Flamingo" or a thick slab of progressive sludginess.
It's difficult to recommend albums because the band has gone through so many changes. I'm partial to the "Earth Band" period so I recommend "Watch" as a good sampler, but the "Angel Station" album is PARTICULARLY moody and evil...if you find it, buy it and love it. You can stare at the cover art for hours.