The Charles Ives Society maintains an online resource that includes a biography by Jan Swafford; a list of tunes borrowed by Ives from other composers, with sound files; a catalogue of Ives’s published works ordered by medium, also with sound files; a descriptive catalogue by James Sinclair ordered by genre, with incipits, performance data, and other listings; and a programming guide that suggests relationships between Ives’s works and specific holidays, months, seasons, topics, and anniversaries.
Above, a rare performance of one of Ives’s pieces for two pianos tuned a quarter-tone apart, played by the Paratore brothers. Today is the composer’s 136th birthday.