In an effort to implement conservation measures farmers have used a variety of production methods, including the use of reduced or zero tillage and cover crops. One benefit of these production methods has been early season weed control. The literature suggests that a variety of mechanisms may be involved, among them the allelopathic effects of phenolic acids. This retrospective analysis addresses the following: How likely are phenolic acid concentrations and environmental conditions in wheat no-till cropping systems for the inhibition of annual broadleaf weed emergence? and Do phenolic acids have a dominant role or are they just one component of a larger promoter/modifier/inhibitor complex? The book covers allelopathic plant-plant interactions, laboratory and field experiments, and future research. It uses a journal format, provides justifications for procedures used, if-then hypotheses, and cons and pros so that readers can reach their own conclusions.