This book was developed by a coding teacher to help her students understand the complicated and confusing coding guidelines for external cause codes.The book takes the guidelines and translates them into plain English and places them into charts for easy reference. It also includes a simplified, easier-to-use index to external causes. This book is based on the Official Coding Guidelines effective October 1, 2020. It is updated every fall. See also Coding Made Easy books on ICD-10-CM, ICD-10-PCS, and E/M coding.