This book begins with an overview of current thinking on bioavailability, its definition, cutting edge research in speciation and advancement in tools for assessing chemical bioavailability in the terrestrial environment. The second section of the book focuses on the role of chemical speciation in bioavailability. Section three addresses bioavailability and ecotoxicity of contaminants and leads into the next section on bioavailability of nutrients and agrichemicals. Subsequent sections provide an overview of tools currently being used and new cutting edge techniques to assess contaminant bioavailability. The last section of the book builds on previous sections in relating bioavailability to risk assessment and how this could be used for managing risks associated with contaminated land.