Richard Burdon Sanderson Haldane, 1st Viscount Haldane, (July 30 1856 - August 19 1928), was an important British Liberal politician, lawyer, and philosopher.

He was born in Edinburgh, and educated at Edinburgh University and Gottingen University. After studying law in London, he was called to the bar in 1879 and was a rather successful lawyer. In 1885 he was elected a Liberal member of Parliament for the Scottish seat at East Lothian. In 1895, he helped found the London School of Economics. In 1905, he was appointed Secretary of State for War in Henry Campbell Bannerman's administration. Haldane, a prominent Liberal Imperialist and close associate of Herbert Henry Asquith, was a strong advocate of British commitments on the continent, and took great steps in preparing the army for participation in a possible European war by establishing the British Expeditionary Force. His tenure also saw the creation of the Imperial General Staff , the Territorial Army, the Officer Training Corps, and the Special Reserve . He was given a viscountcy in 1911, becoming the Viscount Haldane. Upon Lord Loreburn's retirement in 1912, Haldane succeeded him as Lord Chancellor, but was forced to resign in 1915, after being falsely accused of pro-German sympathies.

As the war progressed, Haldane moved more and more to the left. However, he was held back by his ties to the Liberal Party and to Asquith. It was not until the general election of 1923 when Haldane made several speeches for Labour candidates. When the Labour government was formed by Ramsay MacDonald, Haldane was recruited to serve once again as Lord Chancellor. He was also joint Leader of the Labour Peers with Lord Parmoor. Haldane was a vital member of the Cabinet as he was one of only three members who had sat in a cabinet before; the other two had sat only briefly and for junior posts.

Haldane also served as first Chancellor of the University of Bristol, and was elected Chancellor of the University of St Andrews shortly before his death. He wrote several philosophical works, the best known of which is The Reign of Relativity (1921), which dealt with the philosophical implications of the theory of relativity.

Lord Haldane's brother was respiratory physiologist John Scott Haldane, and his sister was author Elizabeth Haldane.

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The Viscount Cave