As is true for all artists with extensive careers, boiling down the Grateful Dead’s sprawling catalog into a single definitive volume—in this case, 32 tracks for an exploration of double-CD length—is a noble goal and a fool’s errand. That said, in terms of hearing the group’s evolutionary trip, this collection does an admirable job. It serves as both a basic narrative and a general overview for anyone too overwhelmed to know where to start. Live albums are still needed to comprehend that element of the group’s appeal, but “Dark Star,” “St. Stephen,” “Sugar Magnolia,” and “Ripple” should pique curiosity about this uniquely American institution.