This book presents an updated overview of Systemic Lupus Erythematosus (SLE). Eleven chapters describe its definition, history, epidemiology, pathophysiology and the factors involved in its development. Its main clinical manifestations, the most commonly used diagnostic criteria and the studies necessary for its evaluation are also explained in a simple manner.The content includes a review of conventional and modern treatments, the most frequent complications, long-term follow-up and the emotional and social impact of the disease on the patient's life. Finally, recent advances and new research perspectives that are transforming the approach to SLE are addressed.This text is intended for medical students, health professionals and readers interested in understanding, in a clear and concise manner, the essential aspects of this autoimmune disease.