Why do I need 43 books about war?
Reading more than three is informative, but like beating a dead horse.
Sun Tzu's The Art of War.
Clausewitz' On War
Victor Davis Hanson's Carnage and Culture.
The underlying essence is irrefutable :
Any war ever not fought to win by all means necessary, has failed.
Including, most likely, cultures which failed to learn the obvious, and consequently left no historical trace.