Sustainability is neither accidental nor last-minute. It requires thoughtful, purposeful, and timely planning. This workbook is intended to provide insights and activities for collaboratives to think about sustaining their health improvement efforts. This workbook can generally be divided into two sections — understanding the money in the system and moving to action. It covers: • Sources of funding to support local initiatives aimed at improving population health or addressing social determinants of health. • Innovations in policy, health care delivery, and financing mechanisms that can be used to improve population health by increasing access to quality care and addressing social determinants of health. This includes examples of innovations, who is participating, and practical takeaways to replicate or adapt in other communities. • Ideas for how to engage payers when developing sustainable financing models, including how to build relationships with payers, with a particular emphasis on Medicaid, who to talk to at state Medicaid offices, and how to code for social determinants of health screening. While this workbook was developed for Health Resources and Services Administration grantees who attended the 2021 Financial Sustainability Workshop Series, developed by the Georgia Health Policy Center, it will be useful to other organizations and collaboratives focused on sustaining health improvement efforts.