Book excerpt: Awareness of the dangers of toxic components in antifouling coatings has raised interest in the potential for nontoxic alternatives. Marine organisms from bacteria to invertebrates and plants use chemicals to communicate and defend themselves. This book explores natural based antifoulants, their ecological functions, methods of characterisation and possible uses in antifouling. The text takes on the challenge of identifying such compounds, designing sustainable production and incorporating them into antifouling coatings.