Traffic are rightly remembered today as titans of jazz-rock and soul -- but on their 1967 debut album, 'Mr. Fantasy,' released 46 years ago this month, Steve Winwood and company were busy riding the psychedelic coattails of 'Sgt. Pepper.'

It's a fascinating outlier in the Traffic discography: They never made another collection like it, and "collection" is the most fitting descriptor for 'Mr. Fantasy,' since the songs have been re-assembled and re-bundled in so many configurations throughout the years that calling it a legitimate album almost feels inaccurate.

The original UK version was an album in the traditional '60s sense, following the Beatles' blueprint of leaving off hit singles (like the groovy, sitar-driven 'Paper Sun' and Dave Mason's irresistibly goofy psych-pop sing-along 'Hole in My Show'). The US version rectified that problem, re-packing the album as 'Heaven is in Your Mind' with those classic tracks included (not to mention a drastically re-tooled track order).

Even without the hits, 'Mr. Fantasy' is a revealing collection, showcasing a band in transition. Some of the material feels a bit dated (Mason's stiar-led 'Utterly Simple,' clearly influenced by George Harrison's recent experiments with the instrument, devolves into a corny Moody Blues-esque spoken word bit), and occasionally the material feels inextricably tied to its era (the stereo-panned vocals and explosions of reverb on 'Heaven Is In Your Mind'), but every inch of these songs are expertly arranged, exploding with raw creativity and instrumental power: 'No Face, No Name, No Number' is a psych-folk gem, laced with Chris Wood's haunting flute and Dave Mason's exotic tambura lines but driven to ecstasy by Winwood's soulful belting. 'Coloured Rain' blends Wood's honky sax and Jim Capaldi's driving percussion into an early blues-rock gem, bested only by the semi-title-track 'Dear Mr. Fantasy,' an expansive masterpiece built on Winwood's aching vocal (not to mention his mesmerizing skills on guitar and organ).

Traffic, of course, was never a traditional rock band. Capaldi was a singing-writing drummer; Wood's reed instruments gave the band a unique flexibility; Mason, the band's short-lived wild card, loved odd instrumentation and wrote firmly with tongue-in-cheek; and Winwood, a young, white Englishman, sang with the husky, hard-lived soul of an early Delta bluesman. It was an strange combination on paper, but the effect was unmistakably vibrant.

Mason didn't stick around long. In fact, he left before 'Mr. Fantasy' was even officially released (He isn't even featured on the 'Heaven Is In Your Mind' album cover); he would re-join the band for their self-titled album in 1968 (at which point they'd more or less ditched the psychedelic approach altogether in favor of tight, soulful rock) and an expansive 1971 tour that produced the live album, 'Welcome to the Cantine.' Ultimately, though, Mason's style never fully gelled with the others': Winwood, Wood, and Capaldi would serve as Traffic's core trio throughout their fruitful classic '70s period.

But even if 'Mr. Fantasy' isn't a representative Traffic album, or even their most consistent batch of songs, it still captures the restless creativity of a band destined for bigger and better things.

Listen to Traffic - 'Mr. Fantasy'