We are celebrating the extraordinary people responsible for invaluable technological innovations that have helped form the world as we know it. Their legacy cements them all in history as some of the brightest and most influential figures who continue to inspire today.

This time we look at mathematician, computer scientist, logician and cryptanalyst, Alan Turing.

**Alan Turing’s Background**

Alan Mathison Turing was born in London on the 23rd June 1912. He showed a great aptitude and interest in maths and science from an early age, performing basic chemistry experiments. As a young boy, he began to theorise upon complex matters such as relativity and quantum mechanics. His private notes on the theory of relativity showed a degree-level appreciation for the subject and heralded his great scientific potential.

**Scientific Beginnings**

After leaving school Alan began his studies in Mathematics at King’s College, Cambridge University, in 1931. He was a diligent student, with his brilliant dissertation proving the central limit theorem. This is a statistical theory stating that “with a sufficiently large sample size from a population (with a finite level of variance), the mean of all samples from the same population will be approximately equal to its mean”. Throughout Cambridge, Alan developed and nurtured his interest in probability theory and mathematical logic, which was to become the basis of his career.

**His Contribution to Science**

Alan was appointed as a fellow of Cambridge University after his time as a student came to an end. In 1936 he wrote a paper entitled ‘On Computable Numbers, with an Application to the Entscheidungsproblem’. Here Alan analyzed the methodical process of problem-solving, focusing on logical instructions and the action of the mind. He developed the proof that automatic computation cannot solve all mathematical problems. This concept became known as the Universal Machine (later named the Turing Machine)- the central concept of the modern computer.

Later in 1936, Alan moved to the USA to study for a Ph.D. in Mathematical Logic at Princeton University. It was only a year after he completed his studies in 1938 that war was declared on Germany. Alan returned to England to join the Government Code and Cypher School and subsequently began work as a cryptologist at their headquarters, Bletchley Park in Buckinghamshire.

At this point in his life Alan undertook his most significant work. He made it his mission to crack the German’s seemingly impenetrable Enigma Code, which they used in their naval communications. Through his ingenious capabilities with mathematics and computing, Alan cracked the code, thwarting the German messaging and saving numerous lives.

He ensured that progress in Bletchley Park’s code-breaking continued to be made by introducing the use of electronic technology, which would allow his fellow code-breakers to work at faster speeds. Through these achievements, Alan became an invaluable asset to the British war effort.

**His Legacy**

By the end of the Second World War, Alan was awarded with an OBE (Most Excellent Order of the British Empire) for his groundbreaking work. By the end of the conflict, he was the only scientist working on the idea of a universal machine that could employ electronic technology to increase the speed and reliability of problem-solving. This resulted in the development of early hardware and the use of arithmetical functions by programming. It was the birth of computer science.

Alan became the Director of Manchester University’s computing laboratory and was elected as a fellow of the Royal Society. He died in 1954.

Since his death, Alan and his achievements have been heavily honoured. To mark the 50th anniversary of his death on the 28th October 2004, a bronze statue of Alan was erected at the University of Surrey. In 2007, a statue of him was unveiled at Bletchley Park. Additionally, the *Princeton University Alumni Weekly* named him as the second most significant alumnus in its history.

Not only this, but Alan was ranked at 21st place on the nationwide BBC poll of ‘100 Greatest Britons’ in 2002. When he was included in *Time* Magazine’s ‘100 Most Important People of the 20th Century’, the accompanying statement emphasised the significance of Alan’s place in history by saying, “The fact remains that everyone who taps at a keyboard, opens a spreadsheet or a word-processing program, is working on an incarnation of a Turing machine”.