The major goals of root canal treatment are to clean and shape the root canal system and seal it in three dimensions to prevent reinfection of the tooth. With the emergence of modern instruments and techniques it is bygone just to extract teeth solely due to periapical disease and endodontic failures. Further the naturally retained tooth will be recognized as the ultimate dental implant. There has been massive growth in endodontic retreatment in recent years. The multiplicity of issues involved in endodontic retreatment is discussed in this book. As per the need for retreatment, the major focus here will be on the identification and management of these challenges explained in a brief and with easy to understand language. This book is student-friendly and includes various recent technologies. A list of references is also provided to encourage further reading.