When Radiohead emerged from hibernation as a heady, electronics-adorned experimental act instead of an arena-friendly guitar group, most fans bought into the new direction. Then again, they could have just been holding on for dear life, waiting for Radiohead to return to rocking form. It was rumored to be doing just that with Amnesiac, a collection of songs recorded during the Kid A sessions but deemed worthy of another, distinct album. If anything, however, Amnesiac takes Kid A one step beyond, further eroding the boundaries between electronic and rock music, and between the pop world and the avant-garde. Where OK Computer established Radiohead as a latter-day Pink Floyd, Kid A and Amnesiac move the group closer to Soft Machine and other iconoclastic progressive-rock acts that refuse to conform to even the loosest standards of rock-band behavior. Unlike Soft Machine, though, Radiohead has stripped itself down to the barest necessities, its spare, almost miserly instrumentation leaving plenty of space for studio tricks and strange structures. There might be more guitars and drums on Amnesiac than on Kid A, but that doesn't mean the band enlists the instruments conventionally. "Packt Like Sardines In A Crushd Tin Box," a more controlled take on electro than Kid A's defining "Idiotheque," builds from a loop of what could be tabla or even Indonesian gongs, while ethereal guitars pass through. "Pyramid Song" actually offers real chords before tripping out into jazz-rock territory, though "Knives Out" gives a tantalizing taste of Radiohead's past. Amnesiac's more jarring songs, like the distorted beat workout "Pulk/Pull Revolving Doors" and "Like Spinning Plates," actually push farther than Kid A, while "I Might Be Wrong" and the New Orleans funeral wail of "Life In A Glass House" point in another direction entirely. Thom Yorke's increasingly minimal vocals, ubiquitous but never overbearing (much like Michael Stipe by way of Robert Wyatt, minus the poetic aspirations), are mumbled red herrings; it's best not to examine mantra-like lines like, "I'm a reasonable man, get off my case" for deeper meaning. Like Kid A, Amnesiac will be dismissed by some as an inconsequential indulgence, a mere sequel, or even a collection of lesser, leftover material. But the truth is, the band shows no intention of turning back. Nothing beats a good surprise, and Radiohead is full of them.