The 12th edition of Ananthanarayan and Paniker?s Textbook of Microbiology has been revised extensively in keeping with the approach prescribed by the National Medical Council of India in the new Competency-based Medical Education (CBME) curriculum, which is aimed at integrating microbiology into a system-based approach to human disease. This new edition is also better suited for the shorter course duration with a focus on the ?must-know? categories of the CBME curriculum. The basic principles of infectious diseases and their control within the hospital and the community have been elucidated in the initial chapters. The section on ?General Microbiology? provides an overview of the major microorganisms associated with human infections, while the section on ?Immunology? addresses aspects that can be applied to human health and disease. Up-to-date content on the recent advances in disease detection, molecular methods of diagnosis, quality control, infection prevention and control, public health and epidemiology, and preventive strategies, including national programmes, has been included. The third section, ?Microbiology as Applied to Infectious Diseases?, which is aligned with the competencies prescribed by the National Medical Council of India, elaborately and comprehensively deals with infections in a system-wise manner. The pattern of discussion is uniform across syndromes, detailing the significant etiological agents of each system, their disease spectra, pathogenesis, clinical features and epidemiology and the approach to the laboratory diagnosis and treatment of each of the clinical entities described. Each of the chapters in this section carries one or more tabular columns summarising the causative agents of the various syndromes of the respective organ system for easy reference and recall. The organisms listed in these tables are colour-coded in keeping with their relative etiological significance with respect to the organ system.