In order to maintain uniform therapeutical standards for all forms of drug formulations and to establish safe and practical standards with respect to both dosage and quality and also to ascertain their bioavailability, the analysis of drugs is required at various stages of production as well as of the finished product. This, therefore, calls for continuous and vigorous efforts to develop new, convenient, reliable, rugged and cost-effective procedures for the analysis of drugs. Organic compounds containing sulphur and nitrogen functions find many commercial applications. This book highlights the role of the analytical instrumentation and the analytical methods in assessing the quality of the drugs in various dosage forms. Simple, cost effective, accurate and rapid methods of analysis of therapeutic agents containing organosulphur and nitrogen functionalities have been discussed and explored.