The document discusses orthodontic diagnosis and the various diagnostic aids used. It describes that diagnosis involves case history, clinical examination, study models, radiographs, and photographs. The diagnostic aids are categorized as essential (case history, clinical exam, study models, radiographs) and supplemental (specialized radiographs, EMG, hand wrist radiographs, etc.). It provides details on components of case history, clinical examination including extraoral and intraoral assessment, and functional examination.