This is a paper informing the work of the King's Fund London Commission. Its purpose is to describe the range of services that may be usefully categorised as intermediate care, devise a typology or taxonomy of these services, report on the extent and quality of literature on intermediate care, present the evidence regarding effectiveness and analyse the findings in terms of main conclusions, policy issues and unanswered questions. The author presents arguments for and against including in a conceptual framework of intermediate care various services that have been given this description. She then goes on to describe a range of existing health care structures for delivering intermediate services. Models are also presented which are ways of organising delivery of care to ensure that patients' transitions from one level of care to another are managed smoothly and cost-effectively. The report concludes with some comments about how to evaluate the literature that has been presented and some observations on the potential for incorporating the intermediate care function into existing or developing systems of care.