This document provides an introduction to health informatics. It begins by defining key related terms like information management, information systems, and informatics. Informatics is described as "the science of information, where information is defined as data with meaning." The document then explains the fundamental theorem of informatics proposed by Dr. Friedman. It states that "A person working in partnership with an information resource is 'better' than that same person unassisted." Finally, the document describes the various categories of health informatics like clinical informatics, biomedical informatics, and nursing informatics and provides examples of domains where informatics is applied, with a focus on health care.