The Unfettered Mind: Writings from a Zen Master to a Master Swordsman. By Takuan Soho.
This is a Zen book, a philosophy work. While this is not a Red Teaming or technical book per se, I think if you are looking to really understand the mindset, the human nature and how to better yourself, this book has a lot of value.
I'm a long time Aikido practitioner, where Zen elements are present in every aspect of the Martial Art. One of my early Sensei requested that we read this book before taking our Shodan (Black Belt exam) and that we write a small work about our minds.
Many years later, I found the book again and I read it. Now after having served in the military and working already as a Red Teamer. I understood the contents differently and I began applying those concepts during the anaylsis phase of the project. The results were surprising.
We must know that it is not enough just to see what the Mind is, we must put into practice all that makes it up in our daily life. We may talk about it glibly, we may write books to explain it, but that is far from being enough. However much we may talk about water and describe it quite intelligently, that does not make it real water. So with fire. Mere talking of it will not make the mouth burn. To know what they are means to experience them in actual concreteness. A book on cooking will not cure our hunger. To feel satisfied we must have actual food. So long as we do not go beyond mere talking, we are not true knowers.
It is a small book, but highly recommended.
Here's Takuan Soho on Red Teaming:
When you look at a tree, see it for its leafs, its branches, its trunk and the roots, then and only then will you see the tree.