ABSTRACT
This chapter provides an introduction to the major principles of single-session therapy (SST) and what constitutes good practice in this field. It may be thought that it is clear what single-session therapy is. First, there is therapy that is designed to last for a single session which is known in the SST literature as single-session therapy 'by design'. This is known as single-session therapy 'by default' in the SST literature. SST is not a new concept in the psychotherapy literature. In his book, Talmon defined single-session therapy 'as one face-to-face meeting between a therapist and a patient with no previous or subsequent sessions within one year'. One-at-a-time therapy is a term that was coined by Michael Hoyt and elaborated by Slive and Bobele to describe the situation where therapy takes place one contact at a time, and one contact may be all the time that is needed.
