The chief role of the office is to provide the public with information regarding the work, history and membership of the House of Commons of the United Kingdom.
It was also one of the first sections to pioneer the use of computers and electronic publication in the House of Commons with the use of Viewdata.
The Service's original aims have changed little in its 45-year history and is still charged with "Promoting public knowledge and understanding of the work and role of Parliament."
The Enquiry Service answers questions from the public on all aspects of the work, history and membership of the House of Commons.
Its means of disseminating information have changed somewhat over time and now puts a greater emphasis on online resources such as the Parliament website and social media.