Some researchers might feel apprehensive about the prospect of investigating 20th century Treasury records, particularly given the complex nature of Treasury Registry systems of the 18th and 19th centuries. But the good news is that the Treasury records of the 20th century are reasonably well catalogued. Mark Dunton aims to lay any fears to rest by giving a historical overview of HM Treasury (including its organisation), before moving to an outline of the main sources, supported by some interesting document examples. Mark Dunton joined The National Archives (formerly the Public Record Office) in 1983 and has considerable knowledge and experience of researching public records, specialising in post-1945 Britain. Mark has also been the lead media spokesperson on the annual release of government files under the 30 year rule since 2006. RSS: Mark Dunton gives a historical overview of HM Treasury, before moving to an outline of the main sources, supported by some interesting document examples.