'Practical lessons in Nonsurgical Endodontics' is based on a clinical worked done by Dr. Md. Ismail Hossain during the period of January 2009 to December 2010 Department of Conservative Dentistry and Endodontics, Faculty of Dentistry, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka. The patients were for follow-up examination will be 3, 6, 12 and 24 months postoperatively. Evaluation Guideline given by American Dental Association and Kirkevang et al. were used in this book. Study population were treated as Acceptable, Uncertain and Unacceptable and PAI scores were used to observe the healing of the periapical Pathosis.