Primary immunodeficiencies (PIDs), now collectively termed inborn errors of immunity, comprise more than 400 distinct disorders and represent a rapidly expanding and complex field. Early recognition and accurate diagnosis are critical to ensuring timely intervention, optimal disease management, and improved long-term outcomes. Inborn Errors of Immunity: A Practical Guide delivers an up-to-date, clinically focused resource designed to help healthcare professionals confidently recognize, diagnose, and manage these conditions across diverse care settings. Key Features: Comprehensive, structured coverage of over 400 inborn errors of immunity Contributions from more than 40 international experts across five continents Stepwise, guideline-based approaches to diagnosis and clinical management Clear explanations of molecular mechanisms and disease pathogenesis with schematic signaling pathways Dedicated sections on clinical features, immunologic testing, and laboratory interpretation Richly illustrated with clinical photographs, imaging, histology, and pathology, forming a unique full-color PID atlas Updated summaries of conventional and targeted therapies with follow-up and monitoring guidance Suitable for students, nurses, residents, clinicians, and researchers seeking a practical reference