This issue of Neurologic Clinics features 17 articles that address the neurologic implications of systemic illnesses. Articles include neurologic presentations of infective endocardititis; neurologic presentations of acid-base imbalance, electrolyte abnormalities, and endocrine emergencies; neurologic presentation of renal disease; neurologic manifestations of systemic lupus erythematosus in children and adults; neurologic complications of respiratory disease; neurologic presentations of nutritional deficiencies; neurologic presentations of gastrointestinal disease; neurotoxicity of radiation therapy; neurologic presentation of lyme disease and syphilis; neurologic aspects of drug abuse; neurologic manifestations of transplant complications; neurologic presentations of sarcoidosis; neurologic presentations of fungal infections; neurologic presentations of cardiac disease; neurologic presentation of AIDS; neurologic presentation of systemic vasculitis; and neurologic presentations of hepatic disease.