When the lead singer of a critically beloved, commercially successful band in its prime releases a solo album, it's a bit like a married man with two kids zipping by in a fiery new Porsche. Something, you suspect, ain't right at home. Sure enough, Thom Yorke has admitted that Radiohead, years-long holder of the title Only Band That Matters, has hit a lethargic patch. Personal lives have grown comfortable, professional momentum has slowed. With the future uncertain, Yorke made The Eraser--which turns out not to be a betrayal of his band but a love letter to it.
From the ethereal melodies to...