Weeds pose a significant threat to the productivity of agricultural and horticultural crops. They are a major menace in agriculture and horticulture, causing a reduction in crop yields when they infest plants. Considering these facts, Weed Science is published to provide fundamental information about weeds, as well as control measures, to students, teachers, and individuals involved in agricultural activities. It is not my intention to claim credit for any original contributions on the subject. Rather, this publication should be seen as a concise compilation of various topics from different sources, including books, bulletins, scientific papers, and websites, which are mentioned in the text or in the selected references.

1. Introduction 2. Classification of Weeds 3. Ecology of Weeds 4. Characteristics of Weeds 5. Beneficial Effects of Weeds 6. Dispersal of Weeds 7. Crop-Weed Association 8. Harmful Effects of Weeds 9. Crop Weeds Competition 10. Methods of Weed Control 11. Formulation of Herbicides 12. Aquatic Weeds 13. Management of Parasitic and Problematic Weeds 14. Mode of Action of Herbicides 15. Degradation of Herbicides 16. Management of Herbicide Residues in Soil 17. Herbicides Interaction