This book is to gather the basic principles of pathology which are relevant to dental students. This brief theoretical information is intended to be adequate so as to allow an effective co-operation with medical colleagues. The treatment planning that dentist may consider not only confined to the oral cavity but it could also include all the medical problems that the individual suffers. In turn, there may be modification in therapy or necessitation to take special percussions.thus the overall aim is to achieve sufficient skills that based on sound pathological principles to recognize, correctly diagnose and aware enough with morphology and treatment of all systemic diseases that may be relevant to the oral cavity.