Who spies an I-Spy book these days? Yet they are not extinct; the series celebrates its 50th birthday this year, and the most recent owner, Michelin, is publishing five new titles, including one about the company’s own fat tyre fellow, Bibendum.

I-Spy on the Motorway recognises that not many flowers, castles, birds or flags present themselves to view at 70mph, and children on car journeys are invited to clock up emergency phone boxes, motorway bridges and hazard signs. I-Spy on a Train Journey, at least, is ecologically sound.

As well as being collectables for borderline anoraks, I-Spy books have survived because they continue to offer a jolly good game. Identifying things and scoring points is perennially amusing and these mildly challenging quizzes can be done by children alone or in company.

A large part of the fun is in looking more closely at things that already interest the viewer - and in looking in peculiar directions. Below Your Feet directs attention towards pavements, drains, carpets, footwear, foot bridges and stiles. Titles such as Birds and Flags make you change the angle of the gaze, and At the Airport (five points for each carrier) does the great service of helping to relieve the ennui of queuing.

The grown-up reader may recall I-Spys nostalgically. The 1950s version of Sports Cars (6d) shows many wonders including the Fairthorpe Electron, “a striking looking car of curves and bulges”, and the sturdy pre-war Mark II Dellow, noted for hill-climbing, which had a fold-down windscreen. The content of the early titles is not only quaint - it is also presented in line drawings.

The cover of the On the Road (1963, 9d) shows a horse-drawn caravan ambling across a single-track, hump-backed bridge. Inside, there is a page of common milestones (five points each). Rescue chaps in jodhpurs stand to attention at telephone boxes, their motorbikes and sidecars parked in front. There is even a patrolette (sic) on a Vespa in a skirt. Her tasks? “Relieving patrols, supplying information, and working on special occasions.” In the Country (9d) has a page about the village smith, an everyday fellow who scores only 10 points.

You can still send off for your I-Spy badge when you notch up 1,000 points, but the I-Spy Club has vanished (and who recalls the great Tribe of Redskins with its bicycle pennant, tie and headband?). The books are sold in bookstores and service stations, not in sweetshops. But their place in popular affection is secure.

I-Spy titles are published by Michelin, Pounds 1.50 each