John Conrad Russell, 4th Earl Russell (16 November 1921 – 16 December 1987) was the eldest son of the philosopher and mathematician Bertrand Russell

Bertrand Russell

Bertrand Arthur William Russell, 3rd Earl Russell, OM, FRS was a British philosopher, logician, mathematician, historian, and social critic. At various points in his life he considered himself a liberal, a socialist, and a pacifist, but he also admitted that he had never been any of these things...

 (the 3rd Earl) and his second wife, Dora Black. Thus, the 4th Earl was the great-grandson of the 19th century British Whig

British Whig Party

The Whigs were a party in the Parliament of England, Parliament of Great Britain, and Parliament of the United Kingdom, who contested power with the rival Tories from the 1680s to the 1850s. The Whigs' origin lay in constitutional monarchism and opposition to absolute rule...

 Prime Minister Lord John Russell

John Russell, 1st Earl Russell

John Russell, 1st Earl Russell, KG, GCMG, PC , known as Lord John Russell before 1861, was an English Whig and Liberal politician who served twice as Prime Minister of the United Kingdom in the mid-19th century....

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Married on 28 August 1946 to Susan Doniphan Lindsay, he had only two daughters, Lady Sarah Elizabeth Russell, born on 16 January 1946, and Lady Lucy Catherine Russell (21 July 1948 - 11 April 1975), neither of whom married or bore children.

The 4th Earl was succeeded by his half-brother, the historian Conrad Russell, who became the 5th Earl Russell.