This book contains the history of the 21 General Councils of the Church. Ever since that day in the year 51 A.D., the Apostles under the leadership of Saint Peter gathered in Jerusalem to take a decision on the question of converts from paganism to Christianity, the Pope, the successor of Peter, called the assembly of all bishops for study and decision-making during some momentous times, and in times of crisis and calamities in the history of the Church. These were the General Councils also known as Ecumenical Councils. In the past 20 centuries there were 21 such Councils in the Church. They derive their names from the places they were held. This little book is intended for the study of all those who, in their thirst for knowledge about the Church, are looking for adequate matter for their intellectual and spiritual satisfaction.