Books like The Upanishads
Juan Mascaró
The Upanishads is 142 pages, about 2 hours 36 minutes at 250 words a minute.
8 books to read next
How long each takes
I Am That 10.1 h 
The Rig Veda 6.3 h 
Bhagavad-Gita 3.4 h 
The Complete Works of Swami Vivekananda 9.7 h 
Teachings of Swami Vivekananda 5.5 h 
Dialogue with Death 4.4 h 
Dictionary of All Scriptures and Myths 15.5 h 
The Hindu View of Life 1.8 h Bar height shows length. Estimated at 250 words a minute.