Resorption in dentistry is a phenomenon associated with either physiologic or a pathological process resulting in the loss of dentin, cementum, or bone, irreversibly leading to mobility of the tooth; and eventually resulting in a dental complication that can lead to tooth extraction. Root resorption of permanent dentition is unfavorable. It is broadly divided as Internal and External Root Resorption.This book educates one regarding the nature of Internal Root Resorption, and the clinical approach to it. This phenomenon mostly goes unnoticed since it is asymptomatic in its initial phase. The radiographic representation also isn't evident until the later stages of resorption. Hence it is the dental practitioner's duty to inspect the cases thoroughly and manage them in time, as time is a key factor for prompt treatment and dictates the prognosis of the tooth.