Reading is an honor and a gift from a warrior or historian who—a decade or a thousand decades ago—set aside time to write. He distilled a lifetime of campaigning in order to have a “conversation” with you. We have been fighting on this planet for ten thousand years; it would be idiotic and unethical to not take advantage of such accumulated experiences. If you haven’t read hundreds of books, you are functionally illiterate, and you will be incompetent, because your personal experiences alone aren’t broad enough to sustain you. Any commander who claims he is “too busy to read” is going to fill body bags with his troops as he learns the hard way. The consequences of incompetence in battle are final. History teaches that we face nothing new under the sun. The Commandant of the Marine Corps maintains a list of required reading for every rank. All Marines read a common set; in addition, sergeants read some books, and colonels read others. Even generals are assigned a new set of books that they must consume. At no rank is a Marine excused from studying. When I talked to any group of Marines, I knew from their ranks what books they had read. During planning and before going into battle, I could cite specific examples of how others had solved similar challenges. This provided my lads with a mental model as we adapted to our specific mission.
Mattis, Jim and West, Bing. Call Sign Chaos: Learning to Lead. 2019. p. 42
In his book Mattis specifically endorses Nathaniel Fick’s One Bullet away, which I have quoted from here previously:
https://www.sindark.com/2016/01/13/fick-on-leaving-the-marines/
https://www.sindark.com/2016/01/09/fick-on-the-mask-of-command/
https://www.sindark.com/2016/01/09/memory-under-fire/
https://www.sindark.com/2016/01/08/marine-corps-rules-of-engagement/
The last quote is a description of Mattis.