The number of diagnosed cases of primary immunodeficiency diseases (PIDs) – a group of inborn disorders of the immune system – is growing rapidly, but misdiagnosis or late diagnosis still occurs in a significant number of patients, with serious consequences. This is the second edition of a practical reference textbook on PIDs that has been widely welcomed by scientists and clinicians from around the world. The new edition has been extensively revised to reflect advances in knowledge and includes various PIDs not previously covered. For each disease, information is provided on definition, etiology, clinical manifestations, diagnosis, and management. This book will represent an ideal resource for specialists when engaging in diagnosis, clinical decision-making, and treatment planning. It will also prove invaluable for doctors in training and other physicians and nurses who wish to learn more about PIDs.