"And the singer explodes, no longer laying back, now letting it fly. It is a raw, ragged sound, but the singer is so far into the moment that he doesn't care, and neither does anyone else. "When I read your lovin' letter, my heart began to sink," he roars with ache and ardor in his voice. "There's a million miles between us, but they didn't mean a thing." This glorious minute of "Trying to Get to You" is from Elvis Presley's 1968 television comeback special, one of 77 previously unreleased performances collected on a new four-CD box set, "Platinum: A Life in Music" (RCA). It affirms that 20 years after his death on Aug. 16, 1977, after countless books, albums, tabloid stories, imitators and Graceland tours have wrung seemingly every drop of mystery from his legacy, there remains plenty to learn about Presley. Or, perhaps more precisely, relearn. For in the last 20 years, the essential truth about Presley has been lost. But the truth of his 23 years of public music making is this: He was the most quintessentially American of singers, an artist who drew no boundaries between Saturday night blues and Sunday morning gospel, middle-of-the-road schmaltz and dirt-road hillbilly country. And he could swing a tune like nobody's business. More than anything else, those two factors--his openness to just about any kind of music and his ability to personalize that music with his unique feel for rhythm--are why Presley mattered, and still matters."