In this handbook, the authors present current research in the study of the biological activity, classification and health and environmental implications of herbicides. The topics discussed include productive degradation of dichlorprop by transconjugant strains; weeds and their mechanisms of resistance to herbicides; application of 31P-NMR spectroscopy to glyphosate studies in plants; lethal and sublethal glyphosate effects on non-target fish species; chemical properties and genotoxic effects of phenylurea herbicides; action mode of triazines and toxic effects on vertebrates; and much more.