The books in Bunch are all arranged by subjects, according to Library of Congress classification. All music books begin with the letter "M", which breaks into three categories:
M is for notated music
ML is for books on the various aspects of music -- history, criticism, biographies, etc.
MT is reserved for instruction and study -- Books on technique, teaching, theory and arranging, and even some printed music as well (etudes, studies, exercises, etc).
Click the links to see a detailed breakdown...