Roberto Assagioli, an Italian psychiatrist, is widely recognized as the founder of transpersonal psychology. He coined the term in the 1960s to describe a psychology that goes beyond the personal self and encompasses spiritual and transcendent experiences.

Abraham Maslow, a humanistic psychologist, studied peak experiences, which are moments of intense joy, awe, and transcendence. He believed that these experiences could lead to personal growth and transformation.

Ken Wilber, an American philosopher and psychologist, introduced the concept of the 'transpersonal self,' which refers to the aspect of consciousness that transcends the personal ego and encompasses the entire universe.

Transpersonal psychology aims to understand the nature of human consciousness, including its spiritual and transcendent dimensions, and to explore the potential for human growth and transformation.

Stanislav Grof, a Czech psychiatrist, conducted research on transpersonal experiences using LSD (lysergic acid diethylamide), a psychedelic substance known for its mind-altering effects.

Transpersonal psychology emphasizes the integration of personal and transpersonal experiences, leading to a sense of wholeness and unity within the individual.

Stanislav Grof coined the term 'spiritual emergency' to describe intense and challenging psychological experiences that can arise during spiritual growth and transformation.

Transpersonal psychotherapy aims to facilitate spiritual development and transformation, helping individuals to connect with their inner selves and experience higher states of consciousness.

Ken Wilber developed the 'Integral Theory,' a comprehensive framework that integrates insights from various fields, including psychology, philosophy, and spirituality, to understand human consciousness and development.

Cosmic consciousness refers to the experience of feeling connected to and unified with the entire universe, transcending the boundaries of the individual self.

Stanislav Grof developed holotropic breathwork, a technique that uses rapid breathing to induce altered states of consciousness and facilitate transpersonal experiences.

Transpersonal integration refers to the process of bringing spiritual experiences and insights into daily life, leading to a more holistic and meaningful existence.

Ken Wilber developed the concept of 'transpersonal development,' which refers to the process of evolving beyond the personal self and accessing higher states of consciousness and spiritual awareness.

Spiritual alienation refers to the experience of feeling disconnected from the world and from one's own spiritual nature.

Roberto Assagioli developed psychosynthesis, a transpersonal psychotherapy approach that aims to integrate the various aspects of the self, including the personal and transpersonal dimensions.