Wilfred Trotter was a British surgeon and a pioneer in the field of psychology, particularly known for his work on the psychology of crowds. He was born in 1872 and became influential in understanding how group behavior affects individual actions. His notable book, "Instincts of the Herd in Peace and War," explores the psychological dynamics of crowds during times of conflict and social change. Trotter's research contributed to the development of social psychology and influenced later thinkers, including Sigmund Freud and William McDougall. He emphasized the importance of instinctual drives in shaping human behavior, particularly in collective settings. His work remains relevant in discussions about mass behavior and social movements.