In the United States, calls for service involving people with mental illness comprise approximately 6-7% of all public contacts. The Boston Police Department (BPD) has responded to this need through a partnership with an emergency service provider, training and an intervention to enhance their response to this population. This chapter examines the history of this partnership and the various steps the BPD has taken, including: mandatory E-learning for all officers, a Co-Responder programme, Sequential Intercept Mapping, Crisis Intervention training, SafetyNet® tracking, and, finally, the Hub and COR model. We will outline the adoption of each of these, as well as implications for both Boston police and vulnerable populations residing in the city. The chapter concludes with a discussion of future directions for BPD and the provision of services to people with mental illnesses living in Boston.