This is the 5th edition of a well-established book Principles of Plant Nutrition which was first published in 1978. The same format is maintained as in previous editions with the primary aim of the authors to consider major processes in soils and plants that are of relevance to plant nutrition.This new edition gives an up-to-date account of the scientific advances of the subject by making reference to about 2000 publications. An outstanding feature of the book, which distinguishes it from others, is its wide approach encompassing not only basic nutrition and physiology, but also practical aspects of plant nutrition involving fertilizer usage and crop production of direct importance to human nutrition. Recognizing the international readership of the book, the authors, as in previous editions, have attempted to write in a clear concise style of English for the benefit of the many readers for whom English is not their mother tongue. The book will be of use to undergraduates and postgraduates in Agriculture, Horticulture, Forestry and Ecology as well as those researching in Plant Nutrition.