A primary source of information for historians is the official records of the British administration. The British kept written records of every key instruction, meeting, transaction, investigation, plan, policy decision and agreement. They attached record rooms with all the important administrative institutions.
The British built specialized institutions like museums and archives to preserve important documents.
Historians gather important information about the provincial administrative system from the reports, memos, notings and letters preserved in the 19th century in the archives and record rooms across India.
For effective administration, the British carried out a number of surveys in the early 19th century.
By the end of the 19th century, censuses of all the Indian provinces were being carried out every ten years. This helped to collect information on the religion, caste and occupation of the people. These surveys have helped historians to collect information about modern India.
Personal diaries of personalities like Jawaharlal Nehru and Sardar Vallabhbhai Patel, newspapers, popular books like The Discovery of India and Glimpses of World History, autobiographies of personalities like Mahatma Gandhi, and accounts of travellers and pilgrims give a deep insight into the lives of the common people.