The Calculus Affair is the eighteenth book that Herge wrote in the Adventures of Tintin. Published in 1956, Professor Calculus is kidnapped in an attempt to force him to give up the plans of powerful sonic device that could be used as a weapon.
Tintin, Snowy and Captain Haddock spend most of the story chasing the kidnapped Professor Calculus.
Professor Calculus, on his way to the train station is picked up by the driver of the the butcher's VW delivery van , thus foiling one of the kidnap attempts.
In the English version of The Calculus Affair, Boucherie Sanzot, has been changed to Cutts the Butcher. On the back of the van, the telephone number is 431. Marlinspike, the home of Captain Haddock, has the phone number 421. In the Calculus Affair, Haddock's phone rings incessantly with orders for sausages, from Cutts the Butchers customers, who seem to have trouble with the rotary phones of the time.