This handbook is an expository companion to the Causal Memory Gravity (CMG) series. Based on the CMG corpus of papers I–XI and accompanying documents, it is written as a readable guide to the core ideas, structures, parameters, predictions, and open problems of the CMG programme rather than as a research article or formal review. The text explains the central CMG picture of causal spacetime memory, the effective nonlocal action and its GR limits, the Dynamic Planck Network (DPN) microfoundation, screening, late-time cosmology, galaxy-scale phenomenology, the emergent photon and fermion sectors, the interpretation of key constants, and the current status of observational tests. It also includes a glossary, a structured overview of the CMG paper series, and a suggested reading order for readers entering the framework for the first time.