PROJECT SUMMARY Significance. The Intensive Longitudinal Behavior Network (ILHBN) provides an unprecedented opportunity to advance and shape the future landscape of health behavior science and related intervention practice. The proposed Research Coordinating Center, the Center for Innovation in Intensive Longitudinal Studies (CIILS), housed at the Pennsylvania State University (Penn State), will bring together an interdisciplinary team to synergistically support and coordinate research activities across a diverse portfolio of anticipated U01 projects to accomplish the Network?s larger goal of sustained innovation in the use of intensive longitudinal data (ILD) and associated methods in the study of health behavior change, and in informing prevention and intervention designs. Innovation. The proposed organizational structure of the ILHBN as a small-world network is motivated by our team?s collective decades of experience with multidisciplinary and multi-site collaborations, and is designed to facilitate information flow, collective decision making, and coordination of goals and effort within the ILHBN. Approach. CIILS consists of five Cores with expertise in management of multi-site projects and coordinating centers (Administrative Core); development of novel methods for analysis of ILD (Methods Core); ILD collection, harmonization, sharing, security, as well as collection of digital footprints (Data Core); ILD design, harmonization and instrumentation support (Design Core); and integration of health behavior theories, translation, and implementation of within-person health preventions/interventions (Theory Core). Key personnel with rich and complementary expertise are supported by a roster of advisory Co-Is at Penn State and distributed consultants who are leaders and innovators in their respective fields. Institutional support and contributed staff time by Penn State provide robust infrastructure, expertise, and ?boots on the ground? to support the operation and coordination activities of ILHBN; and a wealth of additional resources to elevate and broaden the collective impacts of the Network.