According to his publisher, Dan “Da Vinci Code” Brown's latest book, The Lost Symbol, sold more copies in its first 36 hours than any other adult hardback sold in total. (A certain boy wizard is excluded by the artful qualifier, “adult”.) The sales of Brown's book were given a boost by an unprecedented price war. According to The Bookseller, an industry magazine, Waterstone's offered a mere 50 per cent discount – ￡9.49 instead of ￡18.99. Tesco asked ￡7 and Asda ￡5. Asda's book buyer celebrated “fantastic” sales, despite the fact that the store is thought to be losing ￡4 a copy. The old joke is made real: losing money on every sale, but making it up on volume.

Asda's price wasn't even the lowest available. The Book Depository, an online retailer, grabbed headlines with a price of ￡4.99 – whereupon Amazon quickly cut prices to match. These prices have prompted many people in the industry to feats of rhetorical self-flagellation. Industry insiders complained to The Bookseller about “ridiculously aggressive discounting” and asked “how can the book trade take itself seriously?”

To an economist, of course, this all makes perfect sense. Muddled thinking tempts us to speak of “the book trade” as a single sentient being. If it were, discounting a sure-fire bestseller from ￡18.99 to ￡4.99 would make no sense at all. But, happily for Dan Brown fans, the book trade does not have a single voice in charge and it would be illegal to appoint one.