who was Rouse Ball Professor of Mathematics at Oxford University for 25 years. He was awarded the Wolf Prize for Physics in 1988 jointly with Stephen Hawking and shared the Noble Prize in 2020 for physics. He also produced important papers on cosmology, topology, manifolds, and twistor theory, which uses geometry and algebra in an attempt to unite quantum theory and relativity. He is also well known as an author of popular science books.