Evolutionary Ecology of Plant Signals and Toxins: A Conceptual Framework -- The Chemistry of Plant Signalling -- Plant Defense Signaling from the Underground Primes Aboveground Defenses to Confer Enhanced Resistance in a Cost-Efficient Manner -- Allelopathy and Exotic Plant Invasion -- Volatile Interaction Between Undamaged Plants: A Short Cut to Coexistence -- Volatile Chemical Interaction Between Undamaged Plants: Effects at Higher Trophic Levels -- Within-Plant Signalling by Volatiles Triggers Systemic Defences -- Volatile Interactions Between Undamaged Plants: Effects and Potential for Breeding Resistance to Aphids -- Communication in Ant-Plant Symbioses -- Photosensory Cues in Plant-Plant Interactions: Regulation and Functional Significance of Shade Avoidance Responses -- Global Atmospheric Change and Trophic Interactions: Are There Any General Responses? -- Exploiting Plant Signals in Sustainable Agriculture -- Plant Volatiles: Useful Signals to Monitor Crop Health Status in Greenhouses. This book shows the complexity of plant signaling and behavior in an ecological context and is intended to increase our understanding of it. It reflects the multifaceted interactions between plants and other organisms that affect their growth and development. In addition it puts emphasis on the effects of plant signaling and behavior on other trophic levels. This field of research is growing and developing rapidly, and new findings are regularly reported. Thus, this book provides a broader view of the field and represents a valuable reference work on the current state of research.