Allelopathy is a new field of science, as the term Allelopathycoined by Prof. Hans Molisch, a German Plant Physiologist in 1937. However, no standard methods are being used by various workers due to lack of compendium on the Techniques, hence, the results obtained are not easily comparable with each others. Till now lot of allelopathy resech has been done in various fields of Agricultural and Plant Sciences. However, there is no compilation of various Research Methods used. Every scientist is conducting research in his own way. It is causing lot of problems to researchers working in underdeveloped/Third World Countries in small towns without Library facilities. Therefore, to make available the standard methods for conducting allelopathy research independently, this multi-volume book has been planned. Since allelopathy is multi-disciplinary area of research, hence, volumes have been planned for each discipline. Prof. S.S. Narwal has planned this multi-volume Book Research Methods in Plant Sciences : Allelopathy. Three volumes (Volume 1. Soil Analysis, Volume 2. Plant Protection and Volume 3. Plant Pathogens) of this Book were released during the IV. International Allelopathy Conference, August 23-25, 2004 at Haryana Agricultural University, Hisar-125004, India. Volumes 4. Plant Analysis and Volume 5. Plant Physiology will be released in November, 2006. Three volumes (Volume 6. Cell Diagnostics, Volume 7. Chemistry Methods and Volume 8. Weed Studies) are under preparation. This book consists of 12 Chapters, describing the methods to analyse various nutrients in plants. The Book is devided into two Sections : General and Determination of Plant nutrients. The Section I. General, provides very elementary and basic information about the various equipments and apparatus used to determine plant nutrients and preparation of Reagents etc. Further, methods of collecting plant samples and their digestion have been described. In Section II. Determination of Plant Nutrients, 8 Chapters describes methods of determining various plant nutrients (Carbon, Nitrogen, Phospherus, Potassium, Sodium, Calcium, Magnesium, Sulphur, Micronutrients and Toxic metals).