The 2021 ICD-10-CM Expert is a comprehensive textbook authored by the American Academy of Professional Coders (AAPC). This spiral-bound publication provides in-depth information on diagnosis codes for providers and facilities, focusing on the medical subject area. With a total of 1392 pages, this textbook is an essential resource for medical professionals, particularly those in the field of allied health services and medical assistants. Written in English, it serves as a valuable reference for understanding and implementing the ICD-10-CM coding system in healthcare settings.