The first edition of this book was published in 1986 as “Short Textbook of Medicine”, Sixth edition has been the concerted effort of many reputed medical teachers holding important teaching and research positions in India, especially Kerala. All the sections have been done under the supervision of the section editors who have special expertise and proficiency in their subjects., The sections have been closely supervised and updated up to the last half of 2016. Wherever new topics are introduced the source has been indicated., All the section editors and many of the contributors are working in the teaching faculty of medical colleges, and participating in coaching classes for medical entrance examinations, and are also examiners for undergraduate and postgraduate courses in India., The volume of the book: Due to the enormous increase in the information in medical science in the previous decade, the volume of the book has to be increased. Moreover, treatment modalities, information on basic sciences, such as genetics, therapeutics, invasive and non-invasive interventions, instrumentation in health sciences, introduction of molecular tools in diagnosis and treatment, such as specific monoclonal antibodies, have all contributed to the need for additional pages.