We all think about the environment when treating mental illness, but we regard it as secondary to helping symptoms and behaviour. Nidotherapy is the collaborative and systematic process of changing the physical, social and personal environment for people who have failed to respond fully to conventional treatments. It can be given by therapists unqualified in other specific treatment interventions and is highly cost effective, and so offers great advantages in health services constrained by cost pressures. This new edition has been fully revised, and includes new chapters on the principles of nidotherapy, the evidence for its effectiveness, its use in intellectual disability and those of limited mental capacity, the skills needed for nidotherapy, the economic benefits and common misconceptions. This comprehensive guide shows how nidotherapy can be used across the range of mental disorders and gives evidence for its value.