This chapter focuses on the transition process, called the Expert Transition Cycle, which an individual goes through each time they make a transition. It reviews the more traditional models including vocational models, career anchors, psychometric models, work adjustment theories, and psychologically based models as well as ecologically and socially embedded models. It then reviews more contemporary transition process models, focusing on two models, working identity and identity status, which inform the study of identities in transition in the research. Finally, it presents the Expert Transition Cycle, which is the basis for determining how identity changes during a transition. This model includes five stages: Intention, Inquiry, Exploration, Commitment, and Integration.