Books like Music Theory
George Thaddeus Jones
Music Theory is 310 pages, about 5 hours 41 minutes at 250 words a minute.
9 books to read next
How long each takes
Twentieth-century Harmony 5.3 h 
The Music Kit 6.1 h 
Music Therapy 3.3 h Music in Theory and Practice 6.6 h 
The Complete Musician 12.0 h 
Tonal Harmony 9.4 h 
Harmony 6.9 h 
Concise Introduction to Tonal Harmony 8.2 h 
Ear-training and Sight-singing Applied to Elementary Musical Theory 3.2 h Bar height shows length. Estimated at 250 words a minute.