Between institutional stays for manic depression, pop savant Daniel Johnston has recorded a vast and remarkable body of inimitably ingenuous songs, using whatever resources were at hand: a dinky cassette machine or a 48- track studio, playing piano or guitar and singing in a boyishly vulnerable tremble. Equally disturbing in its weirdness and beautiful in its Beatlesque melodicism and loopy invention, Johnston's music is an extraordinary mixture of art and madness. But the fringe-weird product of a pitiable genius carries with it an uneasy air of freakshow exploitation. As difficult as it is to resist his innocent charms, it's no easier to view Johnston's cult- figure prominence (and short-lived major-label contract) without some concern.