The fourth edition is appearing after a decade. In the mean time spectacular developments have taken place in analytical Chemistry which necessitated the revision of the book. A major departure from the earlier edition is the inclusion of Introduction at the beginning of each Chapter giving outline of method to be discussed. There are all together new sections on trace element analysis, lasers in analysis and the safety aspects in chemical laboratory. In view of recent developments, topics such as fullerene, nanotubes, Organic zeolites are included. An additional material in the area of reflectance spectroscopy chemiluminescence, Raman spectroscopy, cyclic Volt asymmetry is added. A light on Karl Fischer technique, corrosion, elements of Radioactivity, is thrown. Few chapters have been rewritten to incorporate new information. Every attempt is made to include new knowledge on the new discovery. This revision should be very useful to graduate and postgraduate students and research workers in analytical sciences.