To have or to be? Is one of the seminal books of the second half of the 20th century. Nothing less than a manifesto for a new social and psychological revolution to save our threatened planet, this book is a summary of t...To have or to be? Is one of the seminal books of the second half of the 20th century. Nothing less than a manifesto for a new social and psychological revolution to save our threatened planet, this book is a summary of the penetrating thought of eric fromm.