This latest edition extends the coverage of the 1985 edition which was described as ``...a remarkably comprehensive and well-refined survey of all aspects of the chemistry of phosphorus.''(Journal of Applied Crystallography). Since then, the importance and relevance of phosphorus compounds has continued to increase over ever-widening fields of science and technology. The aims of this greatly expanded fourth edition remain the same: to deal with the basic material and to highlight more recent advances. The book has been extensively revised and much of the material which has been added is from the literature covering the period from mid-1984 to mid-1989.There is no other book with such a comprehensive and up-to-date coverage of the whole realm of phosphorus chemistry. It is an ideal starting point for anyone entering the field and wishing to acquire a specialised knowledge of the subject. Like its predecessors, it continues to be invaluable as a source book for post-graduate specialised courses. As a reference work it is extremely useful for research workers in phosphorus chemistry and allied fields, such as, food chemistry, agricultural chemistry, biochemistry, medicinal chemistry, ceramics, materials science, electronics, mineral and mining.