This book provides a convincing argument for the view that whole cells and whole plants growing in competitive wild conditions show aspects of plant behaviour that can be accurately described as 'intelligent'. Trewavas argues that behaviour, like intelligence, must be assessed within the constraints of the anatomical and physiological framework of the organism in question. The fact that plants do not have centralized nervous systems for example, does not exclude intelligent behaviour. Outside the human dimension, culture is thought largely absent and fitness is the biological property of value. Thus, solving environmental problems that threaten to reduce fitness is another way of viewing intelligent behaviour and has a similar meaning to adaptively variable behaviour. The capacity to solve these problems might be considered to vary in different organisms, but variation does not mean absence. By extending these ideas into a book that allows a critical and amplified discussion, the author hopes to raise an awareness of the concept of purposive behaviour in plants.