Some of the few that survive three generations and remain vivid may then undergo a makeover and relaunch before coming out of copyright. It happened to Peter Rabbit and to Babar, and, with Noddy currently in rehab, one might have supposed that the picture book heroes of the immediate pre-war vintage have lost their place in the republication chain.
The return of Little Tim and his friends Lucy, Charlotte, Ginger and Towser, is a red letter day for admirers of Edward Ardizzone's casually elegant style. Beginning with Little Tim and the Brave Sea Captain, first published in 1936, and Tim and Lucy Go to Sea, first published in 1938 (pound;9.99 each), Scholastic Press is producing new editions of the 11 tales, with the illustrations nicely refreshed.
A brilliant storyteller, Ardizzone spliced together plot, characters, dialogue and images with effortless-looking co-ordination and neat twists. The books do not grow stale with repeated readings; the narratives unfold and billow at exciting moments when the cross-hatching thickens and boats almost capsize beneath grim watercolour waves.
While the Ardizzone steamboat era puffs on triumphantly, the steam train of Diana Ross's Little Red Engine books runs slowly down its one-track line and heads for the buffers.
Andre Deutsch Classics has brought out new editions of three out of the 10 slim, oblong volumes, omitting the first - The Little Red Engine Gets a Name (1942), in which George Lewitt-Him set the streamlined style - in favour of The Story of the Little Red Engine (1945), in which Leslie Wood took over as illustrator.
The Festival of Britain features in The Little Red Engine Goes to Town and Britain's lead in the space race is celebrated in The Little Red Engine and the Rocket (1956), but neither is likely to be of great interest to current five-year-olds. Many grandparents, however, will regard these brisk exercises in chuffalong Fifties mode irresistible, and it is largely grandparents who dictate what becomes a classic.
Since the death of Janet Ahlberg in 1995, the Janet and Allan partnership is alas no more. Their Jolly Postman, bringer of post-modern correspondence relating to nursery rhyme figures and fairy tale characters (a jigsaw here for Humpty Dumpty, an exploitative promo proposition for HRH Cinderella) is timelessly obliging.
Some complain that Janet Ahlberg's graphic style was a bit Laura Ashley. Actually it was comfy yet sharp, cheeky yet reassuring, a brilliant mix of tricks and treats. The Jolly Postman and Other People's Letters, The Jolly Christmas Postman and The Jolly Pocket Postman are major classics of the insert-packed species.