The Exploring Engagement Fund was established with the belief that arts provide a distinct, powerful public benefit that helps create a vibrant, inclusive, and compassionate society. From 2012 to 2018, the Exploring Engagement Fund supported new approaches that these nonprofit arts organizations used to actively engage more diverse participants. Exploring Engagement Fund projects specifically focused on engaging people of color and low-income participants--two populations of particular interest to the Irvine Foundation because they are often underrepresented among typical nonprofit arts participants. Through project experiments, Irvine and its grantees saw and experienced important impacts while also learning valuable lessons about what it takes to engage diverse participants and the types of changes needed to do this work. This report was informed by project data provided by grantees, interviews with grantees, and review of grant reports. This concluding evaluation report on the Exploring Engagement Fund offers insights, best practices, and considerations for arts organizations and funders who prioritize engagement, diversity, equity, and inclusion. It draws on findings and conclusions from the experience of 113 arts nonprofits leading 119 projects intended to engage more people of color and low-income residents, from 2012 to 2018. [This report was written in partnership with Diane Espaldon. For the summary of this report, see ED604067. For the previous report, see "Experiments in Arts Engagement: Case Studies. Real-World Examples and Practical Tips from the Exploring Engagement Fund" (ED604011).]