USI is a venerable institution which has served the defence forces and the nation for 150 years since 1870. During the Centenary, the Council had desired that a history of USI be written. On the recommendation of General JN Chaudhuri, Dr. Adrian Presenton, professor of History and War Studies, Royal Military College of Canada, was engaged, but the project did not progress. In 2008, Col VK Singh, who had served in USI for 17 years by this time, brought out a comprehensive history of USI on his own as a labour of love. This serves as a reference book for the USI staff. Now at the time of sesquicentennial, it was desired that a shortened version be prepared for wider circulation.  Not many members are aware of the wide range and depth of USI activities. The number of events conducted by an exceedingly small staff is mind boggling. Members will feel proud to go through the book and non-members will get motivated to become members.