With Bob Dylan and The Beatles leading the way, the double LP became a prestige item for rock bands by the early ’70s. Some were simply bloated and padded out, but not Physical Graffiti. The new deluxe edition CD reissue is a reminder of Led Zeppelin’s musical range, from raging blues-rock (“In My Time of Dying”) to raga-influenced psychedelia (“In the Light”) and old-time rock ’n’ roll (“Boogie with Stu”). The reissue includes an additional CD of rough takes and alternate mixes, none of them revelatory but interesting for fans as an example of Zeppelin’s creative process.