The growth in the chemical literature has created a need for this dictionary. The entries included in this dictionary have been carefully selected, improved and modified wherever necessary keeping in view the current thoughts on the subject. We have written this dictionary in the language and style familiar to chemists but our aim is to make all entries understandable to any reader interested in chemistry. It is not a dictionary in the usual sense of a compilation of brief definitions, but rather a descriptive information is given so that it may serve as a useful reference.

The selection of entries was guided by the author`s background as teacher of chemistry. The reactions and structures have been illustrated wherever necessary for better understanding to the reader. The authors sincerely hope that this dictionary is an invaluable reference for students, teachers, researchers, scientist and other professionals dealing with chemistry.