This book consists in a series of essays by the leading author on psychologically informed environments (PIEs). Each essay explores a different aspect of the thinking and the practice of PIEs, going into a depth not explored elsewhere. There is a more personal foreword, and an introduction proves a coherent linking narrative between them all. There is also a companion volume, 'Psychologically informed environments from the ground up: service design for complex needs', as a more basic introduction to the Psychologically informed environments approach, and the PIElink community of practice website. Both books have an innovative dynamic relationship with emerging practice in PIEs, pairing the chapters here with matching pages on the PIElink website, where new developments are discussed on-line and in real time, and are 'unfinished'.