This is a solitary attempt to streamline all the possible information related to citrus nutrition, with emphasis on diagnosis and management of nutrient constraints, employing a variety of state-of-art techniques evolved globally over the years . While doing so care has been taken to include peripheral disciplines so that the discussion becomes more lively and authoritative. An entire array of exclusive subjects has been nicely portrayed with the help of latest data and photographs.1.Plant Nutrition and Defense Mechanism: Frontier Knowledge; Jose M Garcia-Mina 2. Antioxidant System in Citrus under Nutrient Stress Conditions: Latest Developments; Vicent Arbona and Aurelio G?mez-Cadenas 3. Phytophenolic Nutrients in Citrus : Biochemical and Molecular Evidence; Theeshan Bahorun, Deena Ramful-Baboolall, Vidushi Neergheen-Bhujun, Okezie I. Aruoma, Ashok Kumar, Shalini Verma, Evelyne Tarnus, Christine Robert Da Silva, Philippe Rondeau and Emmanuel Bourdon 4. Foliar Nutrition: Current State of Knowledge and Opportunities; Sylwester SmoleD 5. Leaf Analysis in Citrus : Interpretation Tools; Regina Menino 6. Leaf Analysis in Citrus : Developments in Analytical Techniques; E. A. Hanlon, K. T. Morgan, T.A. Obreza and R. Mylavarapu 7. Juice Analysis in Citrus: Latest Developments; Giuseppe Gattuso and Davide Barreca 8. Trunk Nutrition; Mahmoud M. Shaaban 9. Non-destructive Proximal Sensing for Early Detection of Citrus Nutrient and Water Stress; Paolo Menesatti, Federico Pallottino, Francesca Antonucci, Giancarlo Roccuzzo, Francesco Intrigliolo, Corrado Costa 10. Spectral Response of Citrus and their Application to Nutrient and Water Constraints Diagnosis; Lola Suarez and Jos? A. J. Berni 11. Soil Enzyme Activities and Soil Fertility Dynamics; Lijuan Yang and Yolong Yulong Zhang 12. Surfactant and Nutrient Uptake in Citrus; Zora Singh and Ahmad Sattar Khan 13. Rhizosphere lSė