This issue of Infectious Disease Clinics of North America, Guest Edited by Paul Auwaerter, MD, is devoted to Lyme Disease. Dr. Auwaerter has assembled a group of expert authors to review the following topics: Epidemiology of Lyme Disease; Early Lyme disease: Erythema Migrans; Neuroborreliosis; Lyme Carditis; Lyme Arthritis; Pediatric Lyme Disease; Diagnostics of Lyme Disease; Post-treatment Lyme Disease Syndrome; Chronic Lyme Disease; Co-infection: Human Granulocytic Ehrlichiosis; Co-infection: Babesiosis; and Emerging Tick-borne infections: Borrelia miyamotoi, Powassan/Deer Tick virus, Heartland virus, Bartonella.