Health and human services currently face a series of challenges - such as aging populations, chronic diseases and new endemics - that require highly complex responses, and take place in multiple care environments including acute medicine, chronic care facilities and the community. Accordingly, most modern health care interventions are now seen as 'complex interventions' - activities that contain a number of component parts with the potential for interactions between them which, when applied to the intended target population, produce a range of possible and variable outcomes. This in turn requires methodological developments that also take into account changing values and attitudes related to the situation of patients' receiving health care. The first book to place complex interventions within a coherent system of research enquiry, this work is designed to help researchers understand the research processes involved at each stage of developing, testing, evaluating and implementing complex interventions, and assist them to integrate methodological activities to produce secure, evidence-based health care interventions. It begins with conceptual chapters which set out the complex interventions framework, discuss the interrelation between knowledge development and evidence, and explore how mixed methods research contributes to improved health. Structured around the influential UK Medical Research Council guidance for use of complex interventions, four sections, each comprised of bite-sized chapters written by multidisciplinary experts in the area, focus on:- Developing complex interventions- Assessing the feasibility of complex interventions and piloting them- Evaluating complex interventions- Implementing complex interventions.Accessible to students and researchers grappling with complex interventions, each substantive chapter includes an introduction, bulleted learning objectives, clinical examples, a summary and further reading. The perspectives of various stakeholders, including patients, families and professionals, are discussed throughout as are the economic and ethical implications of methods. A vital companion for health research, this book is suitable for readers from multidisciplinary disciplines such as medical, nursing, public health, health services research, human services and allied healthcare backgrounds.