Inspired by friends and colleagues, Ernst Cassirer presented in this work, written during his American exile, a summary of his thoughts, in which his philosophy of symbolic forms is further developed in its main ideas, in a way that is accessible to a broader circle of interested readers. Cassirer reexamines the age-old question of the essence of humanity and answers it by modifying the classical response with far-reaching implications: He defines humans as beings that create symbols and communicate with each other and the world through symbols. "The concept of reason is highly unsuitable for capturing the forms of human culture in their fullness and diversity. All these forms are symbolic forms. Therefore, we should define humans not as animal rationale, but as animal symbolicum.".