Juvenile idiopathic arthritis (JIA) is an arthritis which occurs in children and adolescents. It is a noninfective, autoimmune, inflammatory disease of the joints, commonly occurring in children between the ages of 1 and 6. JIA often presents nonspecific symptoms initially such as reduced physical activity, lethargy and poor appetite. Its first noticeable manifestation may be limping. Children may become quite ill with flu-like symptoms. Persistent swelling around the knee, wrist, ankle and the joints of the hands and feet is a clinical manifestation of the condition. The diagnosis of JIA is difficult to establish as the symptoms can indicate other causes. Therefore, often times, a combination of blood tests, X-rays, analysis of the fluid from the joint and clinical presentation are done for making a correct diagnosis. The goal of therapy in JIA is to enable the child to regain a normal level of physical and social activity. This is done with physical therapy, social support and pain management strategies. Children may also be treated with intra-articular corticosteroid injections and nonsteroidal anti-inflammatory drugs. This book elucidates the causes, symptoms and pathophysiology of juvenile idiopathic arthritis in a comprehensive manner. It strives to provide a fair idea about the modern practices in the management of JIA. A number of latest researches have been included to keep the readers up-to-date with the global concepts in this medical condition.