Recent neuroscience research reflects a new optimism concerning the ability of the brain to remain flexible and benefit from enriched environments throughout life. Psychotherapy is such an enriched environment, tailored to encourage the growth and integration of neural networks regulating memory, cognition, emotion and attachment. This text hypothesizes that all forms of psychotherapy - from psychoanalysis to behaviourism - are successful to the degree to which they enhance plasticity in relevant neural circuits. Many forms of psychotherapy, developed in the absence of any understanding of the brain, are now being supported by findings in neuroscience. The text suggests that the unscientific use of language and emotional attunement, for which psychotherapists are often criticized by those in the hard sciences, may actually provide the best medium for neural growth and integration. The basic premises are that the brain is an organ of adaptation which is first built by early interpersonal experiences and that psychotherapy creates an interpersonal matrix capable of rebuilding it. Written for psychotherapists and others interested in the relationship between the brain and behaviour, the primary goal of this text is to encourage us to consider the brain when attempting to understand ourselves and others. Neural networks dedicated to memory, attachment, fear, imagination and executive control are discussed from a variety of perspectives including evolution, development and the effects of pathological states. The text provides examples of present and potential future applications of neuroscience to psychotherapy.