Dentists are likely to encounter lesions that have both Endodontic and Periodontal aetiological components; the so called 'Endo-Perio lesions'. A thorough examination with appropriate investigations remains pivotal to diagnosing such lesions. Correct diagnosis is therefore the key to successful outcome as it enables the most suitable clinical management hence improving the prognosis. The interrelationship between endodontic and periodontal disease has aroused confusion, queries and controversy. Differentiating between endodontic and periodontal problems can be difficult. A symptomatic tooth may have pain of pulpal and/or periodontal origin. The nature of that pain is often the first clue in determining the etiology of such a problem. Radiographic and clinical evaluation can help clarify the nature of the problem. In some cases, the influence of pulpal pathology may create periodontal involvement. In others, periodontal pathology may create pulpal pathology. This book discusses the various clinical aspects to be considered for accurately diagnosing and treating endo-perio lesions.