Over the past decade, the field of hospital medicine has experienced meteoric growth and is now the predominant model of inpatient care in many hospitals across the United States. The number of practitioners now exceeds 20,000, and the scope of knowledge that is required to effectively practice hospital-based medicine has expanded greatly. One critical factor in this growth is the increasing complexity of hospitalized medical patients, and the need for accountability for both quality and efficiency of care delivery. Hospitalist physicians have become leaders and scholars in a variety of domains in the inpatient setting including patient safety, perioperative medicine and palliative care, in addition to their traditional focus on the comprehensive medical care of hospitalized patients. This issue of Medical Clinics of North America begins with an update on the current state of the field of hospital medicine followed by articles on core areas of hospitalist expertise including patient safety, prevention of nosocomial infection, transitions in care, perioperative medicine and palliative care. This issue also covers core clinical topics in the management of hospitalized patients including pain management, geriatric care, diabetic management, life threatening infectious diseases and thromboembolic disease. It concludes with a review of critical care management issues essential to non-critical care specialists.