Once upon a time, a children's paperback was likely to be a novel. Non-fiction was hardback. Now there is a surfeit of low-priced factual series, mainly devoted to history and science, all relentlessly determined to prove that the subjects they tackle are "fun".
Philip Ardagh's titles for Macmillan are published as WOW! Books. In an unremittingly chatty style, he makes psychoanalysis, DNA and nuclear fission accessible to any 12-year-old who might flick through these cartoon-illustrated pages.
His Events that Changed the World and Inventions that Changed the World are the most straightforward. The rise and fall of Rome, the Industrial Revolution and the development of printing and recorded sound are, after all, fairly easy to describe and assess.
On the other hand, not every scientist might agree that seven short pages in Discoveries that Changed the World are enough to explain the theory of relativity - even if Ardagh's description of "a bendy universe" comes pretty close.
Ideas that Changed the World is particularly good on astrology, Darwinism and female suffrage. Especially intriguing is the chapter on the history of money, from the invention of coins through to plastic money.
John Farman's series for Red Fox - The Short and Bloody History of . . . - is in a similar vein, but the tone is more laddish. The Short and Bloody History of Knights explains that many chivalrous knights "showed two fingers" to the Church and "took advantage" of women "if you get my meanin". And the book on pirates tells us all we need to know about pirates drinking their own pee.
Despite this gung-ho mateyness (or because of it), Farman's books are compelling and informative. The one on spies is particularly good, bringing to life some little-known eccentrics. The Short and Bloody History of Highwaymen is a fascinating canter through some byways of social history.
From Oxford University Press, no less, comes an equally jokey series for slightly younger readers. These How toI books are as much activity as information books. How to Live on Mars by Clive Gifford gives us Blue Peter-style experiments such as building a multi-stage rocket (it requires a paper cup, a long balloon and a round balloon) and making Martian soil (rust), with steel wool, water and a paper towel.
The companion How to be a Genius by Jonathan Hancock includes traditional IQ tests and simple games and exercises to develop logical thought, while How to Build a Robot (also by Clive Gifford) mixes experiments, cartoons and information in a jolly introduction to computers.
The British Museum gets in on the act with its Fun Books by Sandy Ransford. These mainly consist of puzzles and quizzes with a few dire jokes aimed at still younger readers. They include volumes on Ancient Rome and Wonders of the Ancient World. Despite their aggressively populist approach, they convey salient facts on their given topics.
At pound;2.99 each, all these books could happily make classroom rewards or cheerful stocking fillers.