Research on health literacy (HL) has identified the need for a more complex and nuanced understanding of HL that considers patient HL within a larger context that includes other patient-, provider-, and organization-level dynamics. Recent advances in HL research have begun to investigate the role providers and healthcare systems play in shaping individuals' capacities to meet their health-related needs, and the HL-related demands providers and healthcare systems place on patients. We term this more contextualized conceptualization of HL "health literacy systems," and propose to further our understanding of HL systems through the study of patient- provider-organization interactions, processes, and arrangements that comprise two complex care management (CCM) programs, located in two safety-net institutions. With the Affordable Care Act's coverage of formerly UN- and under W insured populations, we need an extended understanding of HL systems that is applicable to safety net settings where the most vulnerable in our society seek care. Safety-net CCM programs explicitly work with, adapt to, and cultivate the often limited HL levels of their high-risk, high-acuity patients, and seek to change at the clinic level the HL demands placed on patients and providers. Thus a study of CCM processes and practices can contribute new knowledge on the conceptualization and measurement of HL, including its extension to the organizational level; "real world," sustainable strategies to provide care to vulnerable populations with varying HL; and team-based interventions that successfully promote HL and patient engagement-the ability of patients and families to take an active role in their own healthcare in partnership with providers. Therefore, the specific aims of this mixed methods project are to: (1) provide a detailed, in- depth ethnographic description of the interactions, processes, and organizational arrangements of CCM programs that contribute to patients' retention in the clinical care system and fulfillment of their social and medical needs; (2) identiy and analyze individual (patient and provider), program, and organization characteristics that enhance or inhibit patient engagement and health literacy systems; and (3) conduct focused analyses of the ethnographic data to: a) develop and cognitively test a patient engagement measurement tool; b) identify and elaborate organizational health literacy domains and attributes critical for safety net institutions; and c) elaborate a conceptual framework linking organizational health literacy attributes to patient engagement. The overall goals of this project are to advance a contextual understanding of HL systems; help define and construct measures for organizational health literacy and improve understanding of the relationship between organizational health literacy and patient engagement.