The title is a stopper, and meant to be. The book is extremely sophisticated, detailed and convincing. 100 or even 50 years ago, no one could have made a case for plant intelligence, but dramatic research findings over the last decades have shown that plants--although they lack nervous systems--have exceedingly complex internal communication, mediated by chemicals (plant hormones, ions, etc.). Trewavas provides full details on the chemistry. There is communication even within cells, but what is impressive is the amount of communication and even decision-making that goes on in the whole plant. It has to decide how to grow toward light and away from shade, toward water and nutrients and away from sterile soil, etc. We once thought this was a simple, automatic process, but the reality has turned out to be as chemically and strategically complicated as decision-making in simple invertebrate animals.