James Mattis is a retired United States Marine Corps general who served as the 26th Secretary of Defense from January 2017 to January 2019. Known for his strategic insight and leadership, he played a significant role in military operations in Iraq and Afghanistan. Mattis is often referred to by the nickname "Mad Dog" due to his tough demeanor and straightforward communication style. Born on September 8, 1950, in Pullman, Washington, Mattis graduated from Central Washington University and later earned a master's degree in international security affairs from National Defense University. He is respected for his extensive military experience and has authored several books on military strategy and leadership.