The style and presentation form has been maintained - simple diagrams, self-explanatory flow charts, tables and student friendly mnemonics. Some new topics like cognitive enhancers, CNS stimulants, Drugs for the treatment of Psoriasis and Acne vulgaris have been introduced. Definitions, treatment schedules as per WHO (for tuberculosis, leprosy, malaria, HIV), RNTCP (for TB) guidelines and classification of blood pressure as per JNC, 2003 guidelines have been included and we acknowledge the same. This extensively revised edition will be useful not only for the students of medicine but also for practicing doctors.