Books like What Is Ancient Philosophy?
Pierre Hadot
What Is Ancient Philosophy? is 384 pages, about 7 hours 2 minutes at 250 words a minute.
12 books to read next
How long each takes
Meditations 3.7 h 
De Rerum Natura 5.2 h 
Phaedo 3.6 h 
The Discourses of Epictetus 8.3 h 
Five Dialogues 3.0 h 
Lives of the Stoics 6.5 h 
Meno 2.1 h 
Theaetetus 3.3 h 
The Stoic Philosophy of Seneca 4.8 h 
Protagoras 2.7 h 
Timaeus 5.1 h 
Readings in Ancient Greek Philosophy 18.2 h Bar height shows length. Estimated at 250 words a minute.