Books like On the Origins of War
Donald Kagan
On the Origins of War is 608 pages, about 11 hours 9 minutes at 250 words a minute.
10 books to read next
How long each takes
Sharpe's Triumph 7.0 h 
A History of Warfare 7.9 h 
The Causes of War 5.4 h 
Makers of Modern Strategy 10.1 h 
Honor Bound 10.1 h 
Call to Arms 6.5 h 
Sharpe's Havoc 7.0 h Men at War 9.3 h 
The Iraq War 5.0 h 
Retreat, Hell! 9.1 h Bar height shows length. Estimated at 250 words a minute.