Pippa Middleton, royal bridesmaid and possessor of the most famous bottom since Velázquez's Rokeby Venus, has signed a book deal for a reported £400,000, after a bidding war won by Michael Joseph, an imprint of Penguin.
The book, a guide to party planning, is due out next Christmas. It is thought that the author was advised to wait until after the Queen's Diamond Jubilee celebrations, so that nobody could accuse her of exploiting her royal connections, although it's hard to imagine any reason other than her royal connections that would justify a publisher spending so much on a party guide. Even if Ms Middleton promised to come round in person to blow up each purchaser's novelty balloons, the likely book sales still wouldn't justify an outlay of nearly half a million quid.
The party tome is a classic Sudden Fame Cash-In Book, a low-brow genre even less dignified than the celebrity memoir. Whereas the latter tends to appear towards the end of a lengthy entertainment career, the former tends to be rushed out in haste soon after the author's first exposure to the public's gaze, for fear that their appeal may not survive the year.
The most recent example is Nancy Dell'Olio, who announced two weeks ago that she is to write a "lovers' guide" (with pictures of herself in saucy knickers). Ms Dell'Olio was known for years only as the hyper-maquillaged Italian girlfriend of the England football manager Sven-Goran Eriksson, but her celebrity was fast-tracked by her appearance on this year's Strictly Come Dancing.
An earlier example of the cash-in author, someone persuaded to produce a book despite having no particular talent or subject, was Christine Hamilton. Known only for her on-camera handbagging of Martin Bell during the 1997 election campaign, when he stood against her husband, Neil Hamilton, she was ridiculed by the press as a classic Tory harridan and Home Counties termagant. So, following the famous advice that when it's raining lemons you make lemonade, she published The Book of British Battleaxes.
Heroic sportsmen are routinely snapped up for autobiographies. Sporting failures have to rely on the fondness of the public in order to cash in. When ski jumper Eddie "the Eagle" Edwards came last in his events at the 1988 Olympics, he expected to slink away in disgrace. But when he became a celebrity, he was able to knock out a cash-in book (On the Piste) while his moment in the spotlight lasted.
Cash-in books aren't restricted to humans, though. In 2009 a successful TV commercial for car insurance appeared featuring a Russian-voiced meerkat. Such was the public's response to the hairy puppet that a book followed in 2010 (A Simples Life: the Life and Times of Aleksandr Orlov); its flood of pre-orders outstripped those for Tony Blair's autobiography. Years earlier, a TV commercial for Yellow Pages followed the creaking attempts of an elderly author, "J R Hartley", to track down copies of his equally ancient book entitled Fly Fishing. He succeeded. The nation wept for him.
And with a certain inevitability, a cash-in book, Fly Fishing by JR Hartley, appeared in the shops at Christmas.
A fictional angler and a cuddly toy mongoose – that's the company Pippa Middleton will soon be joining in the ranks of the cash-in authors.