We will answer this question through a summary we have made of various passages from Stanislav Grof’s book “Transpersonal Psychology”:

«Transpersonal oriented psychotherapies emerged in the 1960s as an expansion of humanistic psychology, which proved too limited to address spirituality and transcendental needs as essential dimensions of the human being. Anthony Sutich and Abraham Maslow, key figures in humanistic psychology, consolidated this new movement known as the “Fourth Force,” although its roots were already present in the earlier proposals of Carl Gustav Jung, Roberto Assagioli, and Maslow himself. The movement was strengthened by clinical research with psychoactive substances, which offered new perspectives on the psyche.

Carl Jung can be considered the first modern psychologist, as he broke with the dominant Cartesian-Newtonian worldview, giving priority to the unconscious, the mysterious, the mystical, the creative, and the religious, as opposed to Freud’s more rational and scientific values.

Transpersonal psychology, unlike traditional psychotherapeutic approaches, is defined more by context than by content. The transpersonal therapist accompanies the patient through any experience—mundane, biographical, existential, or spiritual—always recognizing the cosmic dimension of consciousness and its evolutionary potential. The essence of this approach is its openness to the full range of human experiences, including spiritual and transcendent states».