This chapter begins an exploration of the history of New Thought, tracing its origins to Antiquity and its evolution into Christian Science. It begins with Gnosticism, which emphasized personal spiritual experience for salvation, and examines how the fusion of Gnostic and Eastern mystical ideas influenced Emanuel Swedenborg, who highlighted the material world’s inherent goodness and the role of inner divine sparks in spiritual growth. Alongside the musings of Franz Anton Mesmer, who introduced “animal magnetism” and the mind-body connection, these ideas led to interest in psychological aspects of health and paved the way for practices like hypnosis and psychotherapy. Mesmer’s popularity in America, aided by Charles Poyen’s demonstrations, inspired Phineas Parkhurst Quimby to focus on healing, emphasizing that illnesses stem from false beliefs, which in turn influenced Mary Baker Eddy’s founding of Christian Science and the positive thinking movement shaping contemporary views on health.