James Vance May was an influential American psychiatrist known for his pioneering work in the statistical study and classification of mental diseases. Born in Lawrence, Kansas, he earned his AB from the University of Kansas and later obtained his medical degree from the University of Pennsylvania. May's career spanned various institutions, including the Brigham Hall Hospital, where he led the pathology department, and the New York State Mental Hospital System. His military service during the Philippine insurrection further shaped his understanding of mental health in challenging environments. May was a trailblazer in recognizing mental illness as a significant public health issue, a perspective that was not widely accepted during his time. He served as superintendent of several mental hospitals, including the Matteawan State Hospital for the Criminally Insane and the Boston State Hospital, where he worked until 1936. His advocacy for statistical approaches in psychiatry laid the groundwork for future research and treatment methodologies, marking him as a significant figure in the evolution of mental health care in the United States. May's contributions have had a lasting impact on the field, influencing how mental health is understood and addressed in society.