The Green Plant as an Intelligent Organism -- Neurobiological View of Plants and Their Body Plan -- Charles Darwin and the Plant Root Apex: Closing a Gap in Living Systems Theory as Applied to Plants -- How Can Plants Choose the Most Promising Organs? -- The Role of Root Apices in Shoot Growth Regulation: Support for Neurobiology at the Whole Plant Level? -- Signals and Targets Triggered by Self-Incompatibility in Plants: Recognition of "Self" Can Be Deadly -- Signal Perception and Transduction in Plant Innate Immunity -- Nitric Oxide Involvement in Incompatible Plant-Pathogen Interactions -- From Cell Division to Organ Shape: Nitric Oxide Is Involved in Auxin-Mediated Root Development -- Neurotransmitters, Neuroregulators and Neurotoxins in Plants -- Amino Acid Transport in Plants and Transport of Neurotransmitters in Animals: a Common Mechanism? -- GABA and GHB Neurotransmitters in Plants and Animals -- The Arabidopsis thaliana Glutamate-like Receptor Family (AtGLR) -- Similarities Between Endocannabinoid Signaling in Animal Systems and N-Acylethanolamine Metabolism in Plants -- Regulation of Plant Growth and Development by Extracellular Nucleotides -- Physiological Roles of Nonselective Cation Channels in the Plasma Membrane of Higher Plants -- Touch-Responsive Behaviors and Gene Expression in Plants -- Oscillations in Plants -- Electrical Signals in Long-Distance Communication in Plants -- Slow Wave Potentials - a Propagating Electrical Signal Unique to Higher Plants -- Electrical Signals, the Cytoskeleton, and Gene Expression: a Hypothesis on the Coherence of the Cellular Responses to Environmental Insult -- Characteristics and Functions of Phloem-Transmitted Electrical Signals in Higher Plants -- Long-Distance Signal Transmission in Trees -- Electrophysiology and Phototropism -- Hydro-Electrochemical Integration of the Higher Plant - Basis for Electrogenic Flower Induction -- Signals and Signalling Pathways in Plant Wound Responses -- Root Exudation and Rhizosphere Biology: Multiple Functions of a Plant Secondary Metabolite -- Communication Between Undamaged Plants by Volatiles: the Role of Allelobiosis. Plant neurobiology is a newly emerging field of plant sciences. It covers signalling and communication at all levels of biological organization - from molecules up to ecological communities. In this book, plants are presented as intelligent and social organisms with complex forms of communication and information processing. Authors from diverse backgrounds such as molecular and cellular biology, electrophysiology, as well as ecology treat the most important aspects of plant communication, including the plant immune system, abilities of plants to recognize self, signal transduction, receptors, plant neurotransmitters and plant neurophysiology. Further, plants are able to recognize the identity of herbivores and organize the defence responses accordingly. The similarities in animal and plant neuronal/immune systems are discussed too. All these hidden aspects of plant life and behaviour will stimulate further intense investigations in order to understand the communicative plants in their whole complexity.