Diagnosis is the investigation or analysis of the cause or nature of a condition, situation, or problem. Establishing a proper diagnosis is the first step towards management of any disease. The field of orthodontics deals with the management of Comprehensive orthodontic diagnosis is established by clinical implementation called diagnostic aids. It deals with recognition of various characteristics of malocclusion. These diagnostic aids can be classified into essential, supplementary and recent advancements. This book is designed to help graduate and post graduate dental students and practicing clinicians to easily evaluate a patient with orthodontic treatment needs.