Informatics, the study of the science of information and related disciplines, is being increasingly applied to medicine and healthcare. Medical schools are de- veloping departments, divisions, and sections of medical (or biomedical) infor- matics, and curricula are being created for medical students and residents. For many practicing physicians, questions such as "What is informatics?" and "Why is informatics important in medicine?" are becoming commonplace. Further, once these basics are understood, many physicians seek more complete information about this new "basic science. " The goal of this book is to provide primary care physicians with a practical in- troductory understanding of medical informatics, focusing on areas of importance in primary care. Additionally, we seek to present clinical contexts in which some of the various applications of medical informatics can be applied. The book begins with an overview of medical informatics, based on the inter- action (interface) between the patient and the primary care physician. Next, we study how this interaction can be documented with electronic medical records, and how information on laboratory data and imaging, originating from other elec- tronic sources, can be integrated into the electronic medical record. We then cover several areas that concern the content of the information used in primary care. Areas of focus include evidence-based medicine, decision support, knowledge re- sources, and patient education. Finally, this book concludes with five chapters concerning practical aspects of primary care informatics: workflow, privacy and security, electronic billing, reporting and analysis, and telecommunications.