Ellis also wrote numerous articles and several books. "The New Rhythm Book" (1972) presents methods of practice and performance in unusual meters and features a companion play-along LP/cassette entitled "New Rhythms". His second book, "Quarter Tones", published in 1975, is a theoretical guide to using quarter tones. Both books are thorough, providing a great deal of historical and cultural background to their subjects. "Quarter Tones" also provides readers with etudes and exercises. Both books are hard to find, as they have presumably not been printed since their first editions.