Stephen Hawking is without doubt the most famous scientist alive, and probably one of the top five ever in the public imagination, alongside Einstein and Newton. His image and his electronically generated voice are instantly recognizable, even as far out of context as in an episode of the TV show Star Trek: The Next Generation and TV ads for UK telecom giant BT.

Stephen William Hawking was born on 8 January 1942, pretty well exactly 300 years after the death of Galileo - and the birth of Isaac Newton. His parents came from North London, but had temporarily evacuated to Oxford, where Hawking was born. When he was eight, his family moved to the ancient Roman town of St Albans, best known for its stunning abbey. He took his first degree at Oxford, in physics (as his college, University College, didn't offer his preferred subject of mathematics).

He then made the small in distance but large in impact move to Cambridge University to do postgraduate work in cosmology. He became a fellow, and moved in 1973 to the Department of Applied Mathematics and Theoretical Physics. Since 1979 has held the post of Lucasian Professor of Mathematics, at one time held by Newton.

Hawking has worked on the basic laws which govern the universe. With Roger Penrose he showed that Einstein's General Theory of Relativity implied space and time would have a beginning in the Big Bang and an end in black holes. These results indicated it was necessary to unify General Relativity with Quantum Theory, the other great Scientific development of the first half of the 20th Century. One consequence of such a unification that he discovered was that black holes, a topic he had found fascinating since his postgraduate days, should not be completely black, but should emit radiation (so-called Hawking Radiation) and eventually evaporate and disappear. Another conjecture he has made is that the universe has no edge or boundary in imaginary time. This would imply that the way the universe began was completely determined by the laws of science.

Professor Hawking continues to combine family life (he has three children and one grandchild), and his research into theoretical physics together with an extensive programme of travel and public lectures. He suffers from amyotrophic lateral sclerosis, a disease that affects muscle control, which forces him to use a wheelchair and uses a computer voice synthesizer to speak after an emergency tracheotomy saved his life, but has continued to defy medical expectations by working tirelessly into his 60s despite this debilitating condition.