The archive shows the originals of research papers, articles, speeches, radio lectures and letters prepared in the short life (1912-1954) of a man whose thinking is still used today in system design and in tests of whether computers can be described as behaving like humans.
One of the documents sums up his contribution quite simply. It is a hand-written copy of the caption under his photograph at the National Physical Laboratory, "In 1936 Dr Turing wrote down in mathematical terms the first design for a computing machine which anticipated the later development of the digital computing."
During the Second World War he played a leading role in breaking the coded messages being sent to German forces using the Enigma machine. The electro-mechanical Bombe machine he invented to help this work at the secret Bletchley Park centre is currently being rebuilt by volunteer members of the BCS Computer Conservation Society.
The papers in the archive, often with his own hand-written additions, are complemented by personal documents such as plans for a holiday, family news and details of Christmas presents. Also included are photographs showing him as everything from a five-year-old to a young man coming second in a three-mile running race - he was also an accomplished athlete.
There are also links to other sites with information on him.
"The archive is made up of high-quality scans of documents held in an archive at Kings College, Cambridge, and previously only available to visitors there," says Wendy Hall, BCS vice-president, publications. She is professor of computer science at Southampton University and a member of the university's team that developed the digital archive.
"More than a third of the 2,000 documents in the Kings College archive are now online and it is hoped that the project can be extended to the whole collection," says Hall.
The BCS and the Institution of Electrical Engineers both contributed £6,000 to the project.