Most systems of psychotherapy can be considered in terms of the theory and the advocated practice. Cognitive therapy (CT) is a psychological therapy for emotional disorders, especially anxiety disorders, depression and excessive anger. This chapter is concerned with extracting the essence of cognitive therapy, so that compatibilities and incompatibilities with Christianity can be determined. There are a number of therapies that developed from the mid twentieth century that have concerned themselves with thinking. The main ones are Beck's cognitive therapy, rational emotive therapy (RET) rational emotive behaviour therapy (REBT), cognitive restructuring therapy (CRT), schema therapy and metacognitive therapy. A set of therapies that are arguably cognitive but have a less prescriptive approach to cognitions and less specific focus on cognitive phenomena includes dialectical behaviour therapy (DBT), interacting cognitive subsystems therapy (ICST), acceptance and commitment therapy (ACT), and mindfulness based cognitive therapy.