CURRENT All chapters have been completely updated to reflect the latest knowledge and evidence, and important new chapters have been added, including: \`Systems Biology in Health and Disease,\` \`The Human Microbiome,\` \`The Biology of Aging,\` and \`Neuropsychiatric Illnesses in War Veterans.\`   CONNECTED Harrison\`s covers more global aspects of medicine than any other textbook, and features such chapters as \`Global Issues in Medicine,\` by Jim Yong Kim, Paul Farmer, and Joseph Rhatigan, and new to the 18th edition, \`Primary Care in Low and Middle Income Countries.\`   COMPREHENSIVE No other resource delivers coverage of disease mechanisms and management like Harrison\`s, including world-renowned chapters on HIV/AIDS, STEMI and non-STEMI myorcardial infarction, cancer biology, multiple sclerosis, and diabetes. The Harrison\`s DVD has been expanded to include an extensive video demonstration of the neurological physical examination, and video tutorials on how to perform essential clinical procedures, including: Thoracentesis Abdominal Paracentesis Endotracheal Intubation Central Venous Catheter Placement