The author, Amarjit Singh Bhasin, was born in 1939. Since childhood, he has been interested in Mathematics, particularly in Arithmetic. He was a student of B.A. Mathematics (Hons.) in Calcutta University. Unfortunately, he could not complete the course because of certain unavoidable circumstances, but this could not prevent him from devoting his considerable time to study the essentials of Arithmetic, in the last 35 years. This book is the first attempt made by the author. Many more will follow very soon.