Academic dream research is a world apart from the type of inquiry into dreams that takes place in a therapist’s office. Despite this, it is useful for clinicians to have some knowledge of the assumptions we are making when we work with our clients’ dreams. It also behooves us to know something about the field of dream research because this body of work can shape, guide and update our interventions. This chapter covers a select history of dream research, and offers explanations of the major theories about the function(s) of dreaming. The literature on dream science is vast; this chapter is focused on current and clinically relevant literature.