OBITUARY : Professor Jack Good

10 Apr 2009

OBITUARY : Professor Jack Good
------------------------------

Professor Jack Good, who died on April 5 aged 92, made fundamental 
contributions to probability theory, drawing on ideas developed while 
working as a codebreaker at Bletchley Park during the Second World War; 
later on he advised Stanley Kubrick on the computer with a mind of its own 
in the film 2001 - A Space Odyssey, and popularised the board game Go.

A statistician by training and a county chess champion, Good was recruited 
to Bletchley Park from Cambridge in 1941. By the time he arrived, the 
German Air Force and Army Enigma codes had been broken, but their naval 
Enigma code remained frustratingly difficult to decrypt - a major 
problem at a time when supply lines from North America were being 
threatened by U-boats.

Initially Good was assigned to Hut 8 working with Alan Turing and Hugh 
Alexander, who were already using machines known as "bombes" to discover 
the Enigma wheel settings, based on complex algorithmic "cribs" devised by 
Turing using a branch of probability theory known as Bayesian statistics. 
During this early period, the mathematician Max Newman, working in another 
hut, had established a program to use electronic methods of decipherment 
and had recruited Donald Michie, an Oxford classicist, to help him.

In 1943 Good moved from Hut 8 to the "Newmanry" to work with Michie on the 
use of machine methods for decrypting a German cipher system known as 
"Fish". The first machine, appropriately christened the "Heath Robinson", 
used vacuum tubes, was highly unreliable, and thus required extensive 
statistical work to back it up. A particular problem, apart from the 
frequent failure of the vacuum tubes, was that the paper tapes containing 
the intercepted signals were fed in at very high speed and tended to snap. 
Good recalled being able to tell when the machine was going wrong by the 
sound it made - and even by the smell...../snip/


...Like other members of staff at Bletchley Park, Good was unable to talk 
about his wartime work for many years, though he allowed himself an 
oblique reference to his clandestine past in his car number plate: 007 
IJG.

Later he contributed a chapter on "Enigma and Fish" in Codebreakers : The 
Inside Story of Bletchley Park ( 1994 ), edited by Harry Hinsley and Allan 
Stripp.

Good served on numerous scientific committees and won several awards and 
honours. In 1985 he was elected a Fellow of the American Academy of Arts 
and Sciences.

He was unmarried. 

http://www.telegraph.co.uk/news/obituaries/military-obituaries/
special-forces-obituaries/5132599/Professor-Jack-Good.html

http://www.telegraph.co.uk/telegraph/multimedia/archive/01382/jack_good_1382141f.jpg