Immature necrotic permanent tooth presents a distinctive challenge for the endodontist. Various treatment modalities have been employed to create a hard tissue barrier at the apex, which includes non-vital pulp therapy with calcium hydroxide, apexification with mineral trioxide aggregate. It focuses on the terminologies, history, various materials used and its application advantages and disadvantages. This book is a summary of various treatment plans for management of immature apex depending upon the pulpal status of the tooth, also it describes novel treatment modalities like regenerative endodontics which involve the physiological replacement of the damaged tooth structures. This book is easy to read, student-friendly and includes various recent technologies. A list of references is also provided to encourage further reading.