Preface. Introduction. 1. Burgeoning Resistance Requires New Strategies; J. Gressel. Part I: Herbicide Resistant Weeds. 2. Herbicide-Resistant Weeds in Europe: Agricultural, Physiological and Biochemical Aspects; R. De Prado, et al. 3. Herbicide Resistance in North America: History, Circumstances of Development and Current Situation; D.L. Shaner. 4. Herbicide Resistance Outside North America and Europe: Causes and Significance; B. Rubin. Part II: Herbicide Resistance Mechanisms. 5. Resistance to PS II Inhibitor Herbicides; J.W. Gronwald. 6. Target-Site Based Resistance to ACCase Inhibitors; M.D. Devine. 7. Perturbation of the Transmembrane Proton Gradient and Resistance to AOPP Herbicides; R.H. Shimabukuro, B.L. Hoffer. 8. Target-Site Resistance for Acetolactate Synthase Inhibitor Herbicides; L.L. Saari, C.A. Maxwell. 9. Mechanism of Resistance to Dinitroaline Herbicides; R.J. Smeda, K.C. Vaughn. 10. Cytochrome P450 Endowed Herbicide Metabolism; F. Durst, et al. 11. Glutathione Transferases and Herbicide Metabolism and Selectivity; R. Edwards. 12. Mechanisms of Herbicide Multiple Resistance in Lolium rigidum.; F.J. Tardif, et al. 13. Is There a Multiple Pesticide Metabolizing Cytochrome P450 in Maize? M. Barrett, et al. 14. D-1 Protein Turnover and Sensitivity of Higher Plants to Photosystem II-Directed Herbicides; M.T. Giardi, et al. 15. Penetration, Translocation and Metabolism of Pyridate in Chickpea; R. Gimenez-Espinosa, R. De Prado. 16. Distribution Studies ofPropanil Resistance in a Barnyardgrass Biotype and Elucidation of its Resistance Mechanism; R.E. Hoagland, et al. 17. Mechanisms of Resistance to Protoporphyrinogen Oxidase-Inhibiting Herbicides; S.O. Duke, et al. 18. Metabolism of Chlorotoluron in Resistant and Susceptible Alopecurus myosuroides Huds. Biotypes. A Study Using Plant Cell Suspensions; J. Menendez, et al. Part III: Genetics and Biology of Herbicide Resistant Weeds. 19. Molecular Ecology: its Role in Studying Herbicide Resistance; G. Marshall, R.P. Finch. 20. Genetics of Herbicide Resistance within Weeds. Factors of Evolution, Inheritance and Fitness; J. Gasquez. 21. Effects of Mutation for ALS-Inhibitor Resistance on ALS Activity in Resistant and Susceptible Near-Isonuclear Lactuca Lines; C.V. Eberlein, et al. 22. A Biochemical, Physiological and Molecular Characterization of Herbicide Resistance in Echinochloa spp.; N. Lopez-Martinez, et al. 23. The Potential for the Evolution of Herbicide Resistance: Selection, Characterisation and Polygenic Inheritance of Resistance to Chlorsulfuron in Perennial Ryegrass; R. Mackenzie, et al. Part IV: Biotechnological Approaches to Develop Herbicide Resistance in Crops. Problems and Possibilities. 24. Herbicide Resistant Crops Generated by Biotechnology; G. Donn. 25. Manipulation of Crop Tolerance to Herbicides with Safeners; K.K. Hatzios. 26. Gene Flow Between Crops and Weeds: Risk for New Herbicide Resistant Weeds? H. Darmency. 27. Technological, Ecological and Social Aspects of Herbicide Resistant Crops; W.E. Dyer. 28. Unexpected