Prominent crystallographer, thinker and political activist.

Bernal studied physics at the University of Cambridge and embarked on a career in crystallography. In 1937 he became Professor of Physics, and later Professor of Crystallography, at Birkbeck College, London. He is best remembered for his pioneering work in X-ray crystallography.

But Bernal was not 'just' a physicist, he had a wide range of intellectual interests and activities. His contemporaries called him 'Sage' on account of his seemingly limitless knowledge. He was particularly fascinated by the role of science in society and published books and pamphlets on the subject.

Bernal was a Marxist in philosophy and a communist in politics. Despite this he was recruited by the Ministry of Defence in 1939. Working with the physiologist Solly Zuckerman he tested theories about blast injury by exposing himself to explosions in slit trenches. The two men went on to produce the first detailed survey of the effects of bombing on a civilian population.

A flamboyant and chaotic personality, Bernal led an unconventional domestic life of a notoriously non-monogamous nature. He sat on hundreds of committees and played a leading role in many scientific and political organisations. He co-founded the World Peace Council and was awarded the Lenin Prize for Peace in 1958.