• Each chapter starts with applied information of anatomy, physiology, and pathophysiology, therefore, users will be able to refresh their knowledge and will be able to grip the rationalities of diagnostic and therapeutic approaches. • The Decision-Making Investigation Steps (DMIS) of the book will make easy to deal with difficult settings even for the beginners in this field. • Rare cases and least used investigations are presented with flowcharts, figures, tables, boxes to provide simple and effective way to make familiar with the user. • Written in an easy style so that readers with English as second language will not face any difficulty.