Lapierre, wrote the book after an intense two year-long stay in the slums of Calcutta, where he lived and conducted research. He interviewed many residents with the help of translators and used other methods of primary source research before writing City of Joy. In 1981 Lapierre had founded an association to help children suffering from Leprosy in the slums of Calcutta (Bio Lapierre). Lapierre had a clear emotional connection with the people of Calcutta and their stories, and his optimistic novel reflects the good that he encountered there. He states his story is, “true to the confidences that the people of the City of Joy have shared with me, and to the spirit of this unusual place”(CoJ, Author's Note). His hands on and in depth research automatically gives him a leg up on many other authors who may have a hazier sense of the world they are creating within