Books like Isis Unveiled
H. P. Blavatsky
Isis Unveiled is 660 pages, about 12 hours 6 minutes at 250 words a minute.
7 books to read next
How long each takes
The Occult World 3.3 h 
The Esoteric Philosophy of Love and Marriage 2.4 h 
The Force 1.4 h 
Letters on Occult Meditation 6.9 h 
Madame Blavatsky's Baboon 8.6 h 
Ponder on This 7.9 h 
The Hidden Dangers of the Rainbow 4.9 h Bar height shows length. Estimated at 250 words a minute.