For the diagnosis and detection of brain tumour, as well as to aid the medical practitioners in the investigation of the same, the need of a computer based diagnosis system proves to be helpful. This book is specifically designed to represent the ontological relationship based on particular domain of brain tumour for its improved detection and as a tool for better help to the medical practitioner for their practice in the particular field. Brain Tumour is one of the most deadly diseases, often affecting children and overall has a poor prognosis. Due to marketed resistance to radiation and chemotherapy, the prognosis for patients with Glioblastomas is very poor. This book presents a semantic approach to develop an Information retrieval system to support new medical practitioner. Our intention is to help new professional and clinical guidelines. In this book we discuss the ontology building process using Protégé 4.2 ontology editor and other details. In sum, the book will serve as a guideline for self-study or reference of the subject.