Call Sign Chaos: Learning to Lead by Jim Mattis and Bing West is a leadership book that should be deeply studied and absorbed. Since he focuses on the three levels of leadership: direct, executive, and strategic, I think the book has a place in service academies and ROTC programs, as well as basic, advanced, intermediate level and senior service college professional military education institutions.
It is rich with anecdotes and practical wisdom in a contemporary (relatively - post Vietnam to the present) environment. Most importantly it is model or guide for intellectual preparation for every job. There is no substitute for studying history and using case studies. He and his co-author Bing West magically weave in lessons from the Greeks, Romans, the US Civil War, WWI, the Brits in WWII, the Marines in the Pacific, Korea, and Vietnam and more illustrating the practical application of the benefits of knowing history.
The book could serve as syllabus for an entire PhD program in preparation for military leadership. It is the best list of readings of the classics for the understanding and practice of warfare. I use the example of a PhD specifically to emphasize that General Mattis' example of self-study is something to be emulated and his self-study probably taught him more than any PhD program could have. We should all be such lifelong learners. I would throw away all the service efforts to generate PhDs among officers (except in select cases of course) and push to have our military leaders read and think along these lines. Perhaps if this is read by every newly commissioned officer it will change the course of professional military education for the better for generations to come. I was humbled reading this over the past two days.