He was a virtuoso of the piano who inspired an almost religious fervor in his fans, yet he hated performing and left the concert stage forever at the age of 31. He was a tireless advocate of the technology of recording, an artist who looked forward to a time when mere musicians would be rendered obsolete. He was a notorious -- and, some thought, a deliberate -- eccentric, who muffled himself in scarves and gloves, liberally dosed himself with pills, and once sued Steinway & Sons because one of its employees had shaken his hand too roughly. He lived in hermetic solitude and liked to call himself "the last Puritan,"