Ernest Shurtleff Holmes was an American New Thought writer, teacher, and leader. He was the founder of a spiritual movement known as Religious Science, part of the greater New Thought movement, whose spiritual philosophy is known as "The Science of Mind." He was the author of The Science of Mind and numerous other metaphysical books, and the founder of Science of Mind magazine, in continuous publication since 1927. His books remain in print, and the principles he taught as "Science of Mind" have inspired and influenced many generations of metaphysical students and teachers. Holmes had previously studied another New Thought teaching, Divine Science, and was an ordained Divine Science Minister. His influence beyond New Thought can be seen in the self-help movement.

The New Thought movement is a new religious movement that coalesced in the United States in the early 19th century. New Thought was seen by its adherents as succeeding "ancient thought", accumulated wisdom and philosophy from a variety of origins, such as Ancient Greek, Roman, Egyptian, Chinese, Taoist, Hindu, and Buddhist cultures and their related belief systems, primarily regarding the interaction among thought, belief, consciousness in the human mind, and the effects of these within and beyond the human mind. Though no direct line of transmission is traceable, many adherents to New Thought in the 19th and 20th centuries claimed to be direct descendants of those systems.