During World War II, he left his undergraduate studies at Oxford University for Bletchley Park, to help crack German codes with a small group of mathematicians, which included Alan Turing.
[2] After graduation, he was a teacher at Westminster School, London and then the Royal Military College of Science.
In 1954 he wrote three highly influential papers in the Journal of the London Mathematical Society, laying the foundations of inverse semigroup theory.
The Algebraic Theory of Semigroups was hailed as an excellent achievement that greatly influenced the future development of the subject.
[4][5] Preston was an important contributor to algebraic semigroup theory and a respected head of school during his various Monash appointments from 1963 until his retirement in 1990.