Books like The Spiritual Exercises of ECK
Harold Klemp
The Spiritual Exercises of ECK is 305 pages, about 5 hours 36 minutes at 250 words a minute.
12 books to read next
How long each takes
The Flute of God 3.4 h 
Exercitia Spiritualia 4.2 h 
The Tiger's Fang 3.2 h 
Shariyat-Ki-Sugmad 5.0 h 
Enneagram II 3.5 h 
God of Surprises 3.1 h 
Inner Compass 4.3 h 
The Spiritual Notebook 4.3 h 
Your Heart's Desire 3.9 h 
Fuck It 4.7 h 
The Places That Scare You 3.5 h 
The Book of the Secrets 7.4 h Bar height shows length. Estimated at 250 words a minute.