The collections of the Royal United Services Institute for Defence and Security Studies (RUSI), reflect its history as the oldest defence and security think tank in the world. RUSI was founded in 1831 by the Duke of Wellington and moved to its current home, built by Sir Aston Webb, in 1895. The building at 61 Whitehall, with its double-height lecture hall and galleried library, reflects the founding intention of the institute to be ‘a strictly scientific and professional society, and not a club’. Its unique collection of art works, Library of Military History, archive, furniture and chattels, demonstrate the historical and cultural importance of RUSI over nearly two centuries of forward thinking, free discussion and careful reflection on defence and security matters.