On May 8, 1977, at Barton Hall, on the Cornell University campus, in front of 8,500 eager fans, the Grateful Dead played a show so significant that the Library of Congress inducted it into the National Recording Registry. The band had just released Terrapin Station and was still finding its feet after an extended hiatus. In 1977, the Grateful Dead reached a musical peak, and their East Coast spring tour featured an exceptional string of performances,...