Books like In Defense of Purity
Dietrich Von Hildebrand
In Defense of Purity is 169 pages, about 3 hours 6 minutes at 250 words a minute.
12 books to read next
How long each takes
Nature, Man,& Woman 3.8 h 
The Sacred Prostitute 3.1 h 
Man and Woman He Created Them 13.5 h From Goddess to Mortal 2.8 h 
The Art of Sexual Ecstasy 8.3 h 
The Art of Sexual Magic 7.0 h 
Sex Matters 5.6 h 
Sexual Secrets 7.0 h 
The Act of Marriage 5.7 h 
Eroticism 5.6 h 
Erotism 4.3 h 
Tantra 2.5 h Bar height shows length. Estimated at 250 words a minute.