"The Ghost in the Machine" is a non-fiction book written by Arthur Koestler and published in 1967. The book is a critique of the Cartesian dualism, which posits that the mind and body are separate entities, and that mental processes can be understood independently of physical processes. Koestler argues that this dualism is flawed and that the mind and body are intimately connected and cannot be fully understood separately. He suggests that human behavior and consciousness can be better understood by examining the interaction between the brain and the body, and the ways in which they influence each other. The book also explores the implications of this understanding for fields such as psychology and psychiatry. The book is written by Arthur Koestler, a Hungarian-British author, journalist and political activist who is known for his work in the field of science and philosophy. The book was well-received by critics and is considered a classic in the fields of neuroscience, psychology, and philosophy.