 The official, authorised history of the show and ISIRTA, "The Clue Bible" by Jem Roberts, was published by Preface Publishing in October 2009.Humphrey Lyttelton, primarily known as a jazz trumpeter and bandleader, was invited to be chairman because of the role played by improvisation in both comedy and jazz music.In the first series Lyttelton shared the role of chairman with Barry Cryer but he made it his own (especially once Cryer replaced Cleese as a regular panellist) and continued as chairman until his death on 25 April 2008.