As a kid very interested in war, I read quite a few military history books.
Around age 6 or so, my friends and I found the war section in the library and the photographs of World War II, especially of the bombing of industrial and urban targets by the United States Air Force, made a big impression.
Around age 11, reading The Red Badge of Courage and All Quiet On The Western Front made a big impression by describing personal experiences of the horror and terribleness of war and how it affected people, and how governments and cultures and so on make young men kill each other and die.
Focusing gave me an effective technique for working on my own emotional material, when I had little awareness of such things.
Confessions of an Economic Hitman showed me a lot of specifics I didn’t know about the history of corporate exploitation and control of governments and part of what is really happening in the world as opposed to the stories the corporate news media likes us to think is the real narrative instead.
Speak Peace In A World Of Conflict had a big effect on how I communicate and listen to people, and how I see solutions to problems.