Once, Todd Rundgren recorded an exact replica of ''Good Vibrations,'' just because he could. Now Brian Wilson's recorded his own note-for-note ''Vibrations'' copy -- a few rewritten lyrics or extended passages notwithstanding -- with a better excuse: He's painstakingly duplicating an entire 1967 Beach Boys album that never quite actually existed. SMiLE got consigned to the trash heap, and became the holy grail of rock projects, after other band members openly groused about its wigginess. But though it remained legendarily incomplete, several classic numbers (''Heroes and Villains,'' ''Surf's Up'') did see daylight, and lesser scraps have been widely bootlegged. Hearing its original architect re-create this treasure trove of lost-and-found material with ringers (Wilson's touring band almost does the Beach Boys better than the Beach Boys), you may wonder if this is SMiLE-mania -- not the real SMiLE, but an incredible simulation!
But screw all that, because the mirth and beauty of the work trump any concerns about reassemblage. As ''finished'' by Wilson and lyricist Van Dyke Parks, SMiLE fulfills its 37-year promise, detailing what'd happen if you threw Stephen Foster's parlor folk, Aaron Copland's orchestral Americana, the Four Freshmen, some kiddie pop, and a sound-effects record into an acid-laced blender. With a new melodic idea occurring every 45 seconds on average, it's a gorgeous trip back to a time when anything seemed possible, rendered only slightly melancholy through a four-decade filter of diminished musical expectations. Purists will suggest SMiLE was better off as myth, but I'll take the version of the story where Schubert not only gets to finish his eighth symphony, but tours and sells T-shirts behind it.