初版から70年以上、内科学のグローバル・スタンダードとして君臨する「ハリソン内科学」の4年ぶりの新版。COVIDなどの最新情報（著者にファウチ博士）、1000点以上の豊富な図版などが特色。The most timely and comprehensive updates from the world’s top experts are featured in the 21st edition: Current coverage of the diagnosis and treatment of diseases, from COVID to dementia to sepsis to multiple sclerosis to lung cancer; Updated content that reflects new approved therapeutics and new practice-changing guidelines and evidence summaries; More than 1000 clinical, pathological, and radiographic photographs, diagnostic and therapeutic decision trees, and clear schematics and diagrams describing pathophysiologic processes; Numerous atlases featuring curated collections of important visual aspects of diagnosis and management; Updated and time-saving curation and synthesis of established and new medical literature and studies; Clinically relevant coverage of disease mechanics and pathophysiology, and related therapeutic mechanisms. Prev.ed.: 2018.