It is a pleasure to present the new edition of the Washington Manual subspecialty consult series: rheumatology subspecialty consult. This pocket-size book continues to be an excellent primary reference for medical students, interns, residents, and other practitioners who need ready access to practical clinical information to diagnose and treat patients with a wide variety of autoimmune and rheumatologic disorders. Medical knowledge continues to increase at an astounding rate, which creates a challenge for physicians to keep up with the biomedical discoveries, genomic and immunologic advances, and novel therapeutics that can positively impact patient outcomes. The rheumatology subspecialty consult addresses this challenge by concisely and practically providing current scientific information for clinicians to aid them in the diagnosis, investigation, and treatment of autoimmune and rheumatologic diseases.