The formulation and communication of a clear and accurate case conceptualisation is a central task for the schema therapist and should occur before treatment begins. The main purpose of case conceptualisation is for the schema therapist to develop and work from an accurate understanding of the schema-based maintenance factors assessed to underpin a client’s presenting issues. The application of treatment strategies is always informed by the therapist’s understanding of the client based on this case conceptualisation. Thus, schema therapy has been likened to a form of ‘psycho-surgery’; interventions are tailored to meet the client’s needs at that very moment. A second important function of case conceptualisation is to help engage the client in therapy. The clear communication and understanding that comes from the collaborative formulation process aids the therapy relationship by making the client feel heard and understood, while also helping the client understand themselves better and building mode awareness. By the end of the assessment phase, the schema therapist will document a full schema therapy case conceptualisation and communicate a summary of the most important parts of the case conceptualisation using a schema therapy mode map.