“The Marines’ military excellence does not suffocate intellectual freedom or substitute regimented thinking for imaginative solutions. They know their doctrine, often derived from lessons learned in combat and written in blood, but refuse to let that turn into dogma.”

Mattis takes pride throughout the book in how flexible and creative the Marines are as a military branch. He counts it as part of his legacy with the Marines that he helped to preserve this aspect of the Marine experience, decrying lockstep thinking or overly oppressive bureaucracy, and demanding of his soldiers an intellectual rigor as well as a physical one.

“State your flat-ass rules and stick to them. They shouldn’t come as a surprise to anyone. At the same time, leaven your professional passion with personal humility and compassion for your troops. Remember: As an officer, you need to win only one battle—for the hearts of your troops. Win their hearts and they will win the fights.”

Mattis frequently exhibits compassion for his troops and also for his civilian leaders, even when he disagrees with them or has to have a hard conversation. His commitment to dominating a battlefield or creating a killer Marine soldier does not come at the cost of his humanity as he strives not to publicly humiliate anyone or berate them for things beyond their control. This humanity helps Mattis in his continued promotions to the highest levels in the Marine Corps.

“I had learned in the fleet that in harmonious, effective units, everyone owns the unit mission. If you as the commander define the mission as your responsibility, you have already failed. It was our mission, never my mission.”

Mattis says this while learning how to lead a team of recruiters, which is a mission with a distinctly measurable success rate. As such it would be easy to put the sense of failure or success squarely on his own shoulders, but he insists to his team that they act as one and own the success or failure equally. It is this philosophy that encourages his subordinates to put their all into the mission, to honestly own their own mistakes, and to be willing to reach out to Mattis when they need assistance.