Historically, general practitioners provided first-contact care in the United States. Today, however, only 42 percent of the 354 million annual visits for acute care--treatment for newly arising health problems--are made to patients' personal physicians. The rest are made to emergency departments (28 percent), specialists (20 percent), or outpatient departments (7 percent). Although fewer than 5 percent of doctors are emergency physicians, they handle a quarter of all acute care encounters and more than half of such visits by the uninsured. Health reform provisions in the Patient Protection and Affordable Care Act that advance patient-centered medical homes and accountable care organizations are intended to improve access to acute care. The challenge for reform will be to succeed in the current, complex acute care landscape.