This chapter is a comprehensive reference manual providing information on the Confusion Assessment Method (CAM). The CAM is a clinician rating scale that uses information from patient history, clinical observations and objective cognitive tests to diagnose delirium in older adults. It was developed in order to provide a quick, accurate and standardized method that could be used by non-psychiatrists. A brief history of the instrument's development is provided, along with a description of item content and administration/scoring procedures. Psychometric properties are reviewed and a critical commentary is provided. Key references are cited and in most cases the actual scale is included, giving the reader easy access to the instrument.