Here is a listing of some of great books that I have found useful in my musical life. You might find them helpful in the building of yours!
Beginning Studies in Gregorian Chant Dom Eugene Cardine, OSB Dr. William Tortolano, Translator G.I.A. Publications, Inc. Chigaco, IL, 1975. G-3044 www.giamusic.com
Bridge of Waves: What Music Is and How Listening to It Changes the World W. A. Mathieu Shambhala, Boston & London, 2010. www.shambhala.com
Contemporary Choral Arranging Arthur E. Ostrander and Dana Wilson Prentice Hall, New Jersey, 1986. www.pearsonhighered.com
Gregorian Semiology Dom Eugene Cardine, OSB Dr. Robert M. Fowels, CSULA, Translator Solesmes, 1982. www.solesmes.com
Harmonic Experience: Tonal Harmony from It's Natural Origins to Modern Expression W. A. Mathieu Inner Traditions, Rochester, VT, 1997. www.InnerTraditions.com
This is the "everything" music theory book, and a must for every serious student of music. It will open your eyes to the art of music from the inside out. It changed my ears and my life forever.
Lies My Music Teacher Told Me Gerald Eskelin, D.M.E. Stage 3 Publishing, 1994. www.stage3music.com
The Listening Book: Discovering Your Own Music W. A. Mathieu Shambhala Publications, Inc. Boston, 1991. www.shambhala.com
The Musical Life: Reflections on What It Is and How to Live It W. A. Mathieu Shambhala Publications, Inc. Boston, 1994. www.shambhala.com
The Mysticism of Sound and Music Hazrat Inayat Khan Shambhala Publications, Inc. Boston & London, 1996. www.shambhala.com
The Norton Manual of Music Notation George Heussenstamm W. W. Norton & Company, New York, 1987. www.wwnorton.com
Polyphonic Composition Owen Swindale Oxford University Press, England, 1962. www.oup.com
The Technique of Orchestration, 6th edition Kent Kenna and Donald Grantham, U. of Texas at Austin Prentice Hall, New Jersey, 2002. www.pearsonhighered.com
True Love: A Practice for Awakening the Heart Thich Nhat Hahn Shambhala Publications, Inc. Boston, 1997. www.shambhala.com