This paper introduces an evaluation of community-based, integrated health and social care multi-disciplinary teams (MDTs), primarily serving older people with long-term conditions, undertaken as part of the wider evaluation (2015-2022) of the Integrated Care and Support Pioneer Programme in England (2013-2018). To explain the context within which the MDT evaluation was undertaken, we first outline a brief history of health and social care integration policy in England, describe the Pioneer Programme and the requirements of the national 'longer-term' evaluation of the Pioneers. We then explain our rationale for focusing on MDTs, describe our conceptual framework of MDT functioning and provide a brief description of the evaluation design and methods, highlighting four overarching challenges we faced in undertaking it. We then briefly describe the individual papers that constitute the current supplement.