The California Department of Aging (CDA) created this primer which highlights the person-centered practices in No Wrong Door (NWD) Systems for long-term services and supports (LTSS). It offers insights into how California can incorporate person-centered practices when designing and implementing its statewide Aging and Disability NWD System. The primer is a synthesized review of policy documents, codes and regulations, survey data, program narratives and evaluations, and data reports from NWD-related initiatives.