This volume presents detailed descriptions and analyses of the underlying features, issues and suppositions associated with seed and seedling laboratory bioassays presented in a previous volume. It is, however, broader in scope and substance in that the information provided is relevant to all water-soluble compounds released to soil by putative allelopathic living plants and their litter and residues. It is ultimately an attempt to update and expand the practical guidelines for designing laboratory bioassays that have previously been provided in the literature with the hope that the designs of future seed and seedling laboratory bioassays will become more relevant to field systems. Standard references have been included to provide background and additional details. This volume has been written specifically for researchers and their graduate students who are interested in studying plant-plant allelopathic interactions.