Well into the new millennium, the analog cassette tape continues to claw its way back from obsolescence. New cassette labels emerge from hipster enclaves while the cassette's likeness pops up on T-shirts, coffee mugs, belt buckles, and cell phone cases. In Unspooled, Rob Drew traces how a lowly, hissy format that began life in office dictation machines and cheap portable players came to be regarded as a token of intimate expression through...