Alan Turing (1912 – 1954) was a computer scientist who contributed to the overall development of modern computers. He was an expert in the field of cryptology – the science of making and breaking – or 'cracking' codes. During the Second World War he famously developed a machine that could decipher the secret codes that were being disseminated by the German command to their armies across Europe. These secret commands were made by German cipher machine which the allies codenamed ENIGMA.