The Circular Theory ties physics, philosophy and psychology together with a universal X and Y, M-F, Y-N, T-F, also known as a 50-50 two-state-system. This is an overall guide to the five-hundred-plus books that identify and document Conservation of the Circle as the basis for reality. Quantum entanglement (a circle) is the hidden variable (the constant) in nature (physics, symbolic systems universally).