One of the most classic works of philosophy of all time.
In this wonderful book, Erich Fromm explains how the two modes of existence, "having" or "being," struggle for the spirit of humanity. The mode of existence based on "having" leads man to immense selfishness, a constant worry about losing what he has or what he falsely believes he possesses.
On the other hand, the person who lives to "be" is independent, free, creative, enjoys evolving, and for him, love is a dynamic state of being.
In the book "To Have or To Be?", Erich Fromm skillfully analyzes his thoughts, urging humanity towards a psychological revolution: to counterbalance the empty life that stems from "having" with a meaningful life that stems from "being".