It only took one million streams of Pink Floyd's "Wish You Were Here" to unlock the band's saucerful of trips and conceptual rock theater on Spotify. There are still limits to how far you can go in this galaxy: The solo catalogs of guitarist David Gilmour and bassist Roger Waters are also available; that of the Floyd's late star-crossed founder, Syd Barrett, is not. Also missing and needed: the gently compelling 1978 solo album, Wet Dream, by keyboard player Richard Wright, who died in 2008; and Nick Mason's Fictitious Sports, a 1981 progressive-jazz album issued under the Floyd drummer's name but led by composer-pianist Carla Bley.
Yet there is much left to discover – depending on where you first entered and where you got off – in these records, made by a band that was "First in Space" (as the Floyd declared on a treasured tour sweatshirt I had for many years). This CD-length playlist is just one version of the Alternate Floyd lurking out there. It does not duplicate anything on the Echoes or A Foot in the Door best-of sets. And it ends, rightly, with the spectral voice and lyric wit of Barrett, who remained the Floyd's guardian conscience, long after he went his own way.