This thorough study recognises the growing awareness that an integration of functional and causal explanation is required in behavioural analyses...The authors appear to have been remarkably successful..basic concepts have been precisely defined; the link with physiology, in particular with the physiological state of the animal during specific parts of behaviour, is exactly explained, also by using appropriate graphics, flow-charts, and photo sequences...the authors have been capable of a true expansion of theory in several fields of ethology. A separate summary with every chapter considerably enhances the easy use of this fine book - Crustaceana