Mark Vonnegut is an American pediatrician and memoirist. He is the son of writer Kurt Vonnegut, Jr. and his first wife, Jane Cox. He is also the brother of Edith Vonnegut and Nanette Vonnegut. He described himself in the preface to his 1975 book as "a hippie, son of a counterculture hero, BA in religion, genetic disposition to schizophrenia."
Mark Vonnegut graduated from Swarthmore College in 1969. He briefly worked at Duthie Books and was also briefly chief of a 20-man detachment of special state police that provided the security for Boston State Hospital. During the Vietnam War, he filed an application with the draft board to be considered a conscientious objector, which was denied. After taking the psychological examination, he was given a psychiatric 4F classification and avoided conscription into the U.S. military.
During his undergraduate years, he set out to become a Unitarian minister. He eventually abandoned that goal.
He is the author of The Eden Express, which describes his trip to British Columbia to set up a commune with his friends and his personal experiences with schizophrenia, which at that time he attributed to stress, diet and in part, drug use. The book is widely cited as useful for those coping with schizophrenia.