Of course, ideas that good don't die; they hibernate out of sight until it's safe. And now that an '80s revival is in full bloom, the handsomely compiled and annotated Tangent 2002 reintroduces techno's pop genes, implying that we can learn about the future by mining the past. We can, some of the time. Much disco nouveau remains frozen in the lab the New Wave Hits comps left it in -- a great thing in itself, but hardly the future. Yet other test-tube solutions -- the electro-pop, techno-pump, cyber-funk mixed by a cast of international experts like Dutchman Legowelt, Ann Arbor's Ectomorph, Italy's Mat-101 -- are the kind of dance records one could hear at weird warehouse parties and perfunctory 20th-anniversary high school reunions. Back to the future, indeed.