How Spam saved the free world's bacon: The Post-it is in, but the pacamac is past it. John Windsor dips into a new book which celebrates the century's great inventions, some now consigned to the dustbin of history

A moment's silence, please, for the light-brown Smartie. Conceived in 1937 - along with red, yellow, orange, green, mauve, pink and dark-brown ones - it was last seen in 1989, when the German-made blue Smartie replaced it. France, Italy, Belgium and the Netherlands had already submitted to the bright- blue invader when Nestle Rowntree adopted it 'temporarily' in the UK in celebration of the brand's 50th anniversary. It outshone the brown, ousting it within two years.

Light-brown Smarties, Hula-Hoops, Dinky Toys, Green Shield Stamps, long- playing records, pacamacs, red telephone kiosks, Rubik's cube, Spangles and the Sinclair C5 tricycle are some of the 20th- century innovations - commemorated in a new book - whose production lines have fallen short of the millennium.

Peter Cook and Dudley Moore killed the pacamac. LPs, red telephone kiosks and the cube still have loyal followings. But who sheds a tear for that wartime cosmetic, Cyclax Stockingless Cream, at 5s 6d a jar, which gave women's legs the appearance of being encased in another 20th-century invention, nylon?

You will not find anoraks, duvets, central heating or double glazing in this book: all were invented before the turn of the century (the anorak, the 20th-century's antidote to sexual dimorphism, is actually traditional Eskimo wear, originally in male and female versions). But you will find such household words as Aspir-Vess, the Atome, the Epsicle, the Chinese gooseberry, terra-surfing, the Ready Fastener and the Piggly-Wiggly.

Household words? The original names of some 20th-century inventions would not stick. Aspir-Vess, a mixture of aspirin and bicarbonate of soda concocted in the Twenties by Miles Laboratories of Elkhart, Indiana, as an in-house remedy for coughs and sneezes, was marketed as Alka-Seltzer. The Atome was French couturier Jacques Heim's skimpy two-piece ladies' swimming costume, advertised by sky-writing in Cannes in the summer of 1946 as 'the world's smallest bathing suit'. The first bikini? Three weeks later, Heim's rival Louis Reard's sky-writing announced: 'Bikini - smaller than the smallest bathing suit in the world'.

Epsicle was the original iced lollipop, introduced by Californian Frank Epperson in 1923 ('popsicle' stuck in the United States). Kiwi fruit shed its correct name, Chinese gooseberry, in order to woo its middle-class market. The kids who bought the first, hand-made skateboards for dollars 8 each from the Val Surf Shop in Dana Point, California, in 1958, were told that they were for 'terra-surfing'. The zip started out as the Ready Fastener and Piggly-Wiggly was the name of the first self-service supermarket in Memphis, Tennessee, in 1916. Although 2,800 Piggly- Wigglies sprang up in the next seven years, the name never achieved generic status. By the way, what do you think Harry Pickup invented? Correct. Harpic.

Geoff Tibballs, author of the book, Innovations: the 20th Century from Aerosol to Zip, published by Guinness ( pounds 14.99), worked in television for 15 years before becoming a full-time author. He says he has a soft spot for quirky household items, but the book contains few of the idiosyncratic Heath Robinson-style knick-knacks typical of Victorian and Edwardian invention, such as the eye-shield for grapefruit- eaters. You have to refer to an addendum to find 20th-century internally worn cheekpads (for the emaciated), a child- spanker and moustache-guard.

In the 20th century, invention got serious. Big companies institutionalised it

as 'research and development', giving product development managers specifications of newly revealed market niches and telling them: 'Invent that]'

Pentel founder Yukio Horie ordered his researchers to design a pen with a smooth black line like Japanese brush characters. Three years later, in 1962, they came up with the fibre-tip. Bird's Eye's fish fingers were intensively test-marketed, replacing horrid, bony Herring Savoury. Both Perspex and the photocopier were invented to satisfy known needs.

Most mercenary of all: the safety razor. At the turn of the century, King Camp Gillette took this advice from the inventor of the crown bottle-cap, William Painter: 'Think of something that will be used once and thrown away. Then the customer will come back for more.' He meant us.

Considering the pressures of modern retail trading, it is surprising how many money-spinning alternative uses of existing products and by-products remained unexploited for so long. Non-stick Teflon, chanced upon in 1938, was used for fishing rods until 1954. Kimberley-Clark developed cellulose wadding (soft paper tissue) as a First World War substitute for cotton wool. Not until the Twenties, when customers wrote saying it was great for nose- blowing, was Kleenex born.

Similarly, self-adhesive Post-it notes were accidentally invented in 1970 by Spencer Silver, a researcher at the American 3M Corporation, whose brief was to create the world's strongest glue. One of his glues stuck to nothing for very long but was re-usable and left no residue. He painted a notice-board with it. Useless. People still preferred drawing-pins. It was not until he noticed a friend flagging his church hymn book with paper strips that kept falling out that the destiny of his 'useless' glue dawned on him.

Some familiar products were never intended for ordinary consumers. Air-conditioning was invented in 1902 to de-humidify warehouse stocks of paper. The first Airfix model in 1948 was a promotional replica of a Fergusson tractor.

Discovery by chance is rare. Even Christopher Cockerell's tinkering with tin cans and a vacuum-cleaner had nothing random about it. He knew what he was looking for. But when his dream, the Hovercraft, emerged, it nearly did not get off the ground, thanks to tired minds asking 'What is it?'

Aircraft companies smirked that it was not an aircraft, shipping companies chortled that it was not a ship. It languished on the Ministry of Defence's 'secret' list for more than a year because brass hats thought it might be something military.

In the century of the industrial design team, the Cockerell-type lone inventor is not completely extinct. Typewriter correction fluid was invented by a 17-year-old Dallas secretary (and rotten typist), Bette Nesmith Graham, whose other claim to fame was as mother of a member of the Monkees pop group, Michael Nesmith. She adapted the tempera waterbase paint she had seen signwriters use. Her kitchen became a laboratory and her garage a bottling plant. IBM rejected her invention.

Other 20th-century products have been slow to catch on, not because of rejection but because early versions were no good - or downright dangerous. Electric blankets were responsible for 2,600 fire insurance claims in 1956 and killed 20 people over a three-year period. Disposable paper nappies, now with more than 90 per cent of the nappy market in most developed countries, had only 1 per cent in 1956, and for good reason: they were expensive and leaked. Procter and Gamble's original design, worn inside plastic pants, was launched that year in Dallas, where the 93F air temperature gave heat rash to the plastic-wrapped babies.

The 20th century's least acclaimed designer product is probably the Boy Scout. The movement's founder, Robert Baden- Powell, had despaired at the sight of 'thousands of boys and young men, pale, narrow-chested, hunched-up, miserable specimens, smoking endless cigarettes'. Come back, BP, all is forgiven. Mr Tibballs points out that, for 20th-century shirkers, the only place worse than a Scout troop was in another of the century's inventions, the holiday camp. He writes that the only thing missing from the first, Dodd's Socialist Holiday Camp at Caister-on-Sea, Norfolk, in 1906, was the prefix 'concentration'. Campers under canvas were fined sixpence for untidiness, and expelled if caught talking after 11pm.

The century has shown two ways in which innovation can be made to blossom. First, a single technological advance can enable development in a multitude of products. Kitchen appliances awaited the electric motor, consumer technology (radios, mobile phones) took off with the transistor, detergent made possible battalions of automatic washing appliances. And, of course, there was frozen food.

The other way is to start a war. The two world wars - and the Suez conflict - have been the biggest impetus for the inventions in Mr Tibballs's book: the aerosol, ballpoint pen, bikini (wartime fabric rationing), Dettol, Doc Martens boots (made from war-surplus sponge rubber), Durex (output tripled when German condom supplies were cut off), Harpic (originally made from First World War acid waste), the Mini car (Suez petrol rationing), soft paper tissue, soya meat, T-shirt (US Navy issue after Pearl Harbor, on account of its 'greater sweat absorption'), zip - and Spam, Mr Tibballs's favourite 20th-century invention, 'mocked, reviled, but a foundation of Allied victory'.

I will settle for a light-brown Smartie. Packaging collector Robert Opie says there should still be some around, five years after their demise. Readers who send me samples are assured their contributions will not be put on display. I shall eat every one.

(Photograph omitted)