A is for apple. But that is just the start. Collectors in the international market for children's ABC books have paid as much as pounds 35,000 for a scarce specimen. Dubbing themselves alphabetographers or abecedarians, they swap trade gossip and perform lexicographical feats in their own monthly journal, launched in New York last June. Example: create an alphabet of antonyms - pairs of words with opposite meanings.

Founder of the journal, called N is for Newsletter, is Nyr Indictor, a former director of Sotheby's Japanese department in London. Guest writers provide essays on such topics as 'The Vexing X'. His bibliography of ABC books contains 1,200 titles, but he reckons more than 5,000 have been published.

Important ABC books, such as a previously unrecorded 1661 alphabet of children's names by 'S T', would fetch pounds 5,000 at auction today - 10 times the book's price at Sotheby's London in 1970.

Justin Schiller, the New York children's book dealer (who created a stir at Christie's South Kensington last month with a bid of pounds 8,580, 12 times estimate, for a Beatrix Potter drawing, Mice Dance) is asking dollars 65,000 for a copy of the world's most highly priced alphabet book - William Nicholson's An Alphabet (1898), with 26 of his woodcuts, all signed, one of fewer than 20 copies known to have left the publishers.

Kate Greenaway, the Victorian illustrator of sun-dappled children in 18th-century costume, and her contemporary, Walter Crane, command prices more suited to beginners' pockets: Greenaway's A Apple Pie (1886) might cost pounds 40- pounds 60 from a dealer, and Crane's An Alphabet of Old Friends (1875), in good condition, pounds 50- pounds 75.

Learn to spot ABC books whose titles conceal their ABC-ness, Mr Indictor advises. Many, such as An Odd Bestiary or Alliterative Anomalies for Infants and Invalids, are alphabet books. N is for Newsletter calls them 'bashful' titles.

On book-hunting expeditions in junk shops and public-library sales in New York and London, Mr Indictor regularly pays a couple of pounds for pre-war alphabet books that would be priced by specialist dealers at pounds 40 or so. Prices have risen since the appearance of his journal, he says: 'But spreading information is more fun than keeping secrets and paying less.'

Quaritch, the London book dealer, pays some of the highest auction prices on behalf of abecedarians, such as pounds 2,300 for a copy of Queen Charlotte's Primer (1771) at Sotheby's last June. (Remember, if you wish to hold your head high among abecedarians, 'primer' is pronounced 'primmer' and not as in paint.) Satirical verses in alphabetical form by Vladimir Mayakovsky - the Russian poet who defended Communism, then shot himself - sold for pounds 7,840 four years ago at Sotheby's, which seems to have cornered the international ABC auction market.

The bigger the name - Mayakovsky, for example - the bigger the price. Unabashed, or perhaps inspired, by the childishness of the ABC format, Bertrand Russell, the philosopher, published the subversive Good Citizen's Alphabet (1953), whose first edition of 100 is now worth more than pounds 200 a copy from dealers, and the trade edition pounds 30. 'Virtue - Submission to government' is one of its illustrated definitions.

Whenever alphabetarians gather, the conversation will turn, sooner or later, to 'the X problem'. 'X is for Xerxes' is, historically, the commonest solution - less obvious than xylophone or the modern X-ray. You hear fewer arguments over Z. 'Z is for Zebra' - that's easy.

Anyway, enough of that. Alphabetologists now have their own shrine - the passenger travellator at Heathrow airport. Last year, a subscriber to N is for Newsletter noticed that its walls were decorated with man-sized alphabets of place names: Ascot to Zennor at home, Amsterdam to Zagreb abroad, and X represented by Xanadu and Xanthe - a jeu d'esprit by designers Minale Tattersfield & Partners. Is it the world's biggest printed alphabet? Assiduous alphabetologists bombarded Heathrow managers with questions. The Newsletter has now invited its readers to seek other 'alphabet landmarks'.

ABC books originated, of course, as an aid for children learning to read. The nursery rhyme 'A was an apple pie, B bit it, C cut it, D dealt it . . .' has been well known since Charles II's day. But as early as 1742, when 'A was an archer' first appeared - referred to by collectors as the Tom Thumb Alphabet - the adult world began to intrude. Tom Thumb has: 'A was an archer who shot at a frog, B was a butcher, and had a great dog, C was a captain, all covered with lace, D was a drunkard, and had a red face . . .' Studious children went on to read of a gamester, a miser, a robber and a usurer.

The top-priced 1898 Nicholson alphabet was censored by its publishers, Heinemann, who removed Executioner and Topers as unsuitable for children, replacing them with an Earl and a Trumpeter. The Fine Art Society, London picture dealers, sold a 'special' copy, with each illustration signed like Mr Schiller's, in 1991 to a British buyer for pounds 35,000 - a singularly high price for an ABC book, thanks to its 'cross-over' value in the limited-edition artists' print market. Heinemann's archive still has 'several' of the 10 copies it kept - enough to torpedo the price if put on the market at the same time.

Nicholson, like other artists, authors and philosophers, latched on to the alphabet as a showcase for adult virtuosity - in his case, bold Lautrec-style woodcuts. Creators of alphabets, unlike the calligraphers and letter cutters featured by Jonathan Glancey in Weekend last Saturday, have taken the vital step from designing perfect As and Bs to producing a page of stimulating text and graphics. The innocence of the ABC format is a perfect foil for adult subversiveness.

George Cruickshank was the first illustrator's name to appear on an ABC book. A copy of his satirical Comic Alphabet of 1836 sold for pounds 495 at Sotheby's in 1987. Edward Lear contributed zany (useful Z-solution) alphabets to compilations of children's tales published in the 1870s, now collected and reprinted. The Victorian cartoonist Phil May, famous for conveying comic low-life encounters in a few flourishes of the pen, drew two humorous alphabets entwined with East End characters in 1897. The London dealer, Barbara Stone Rare Books, has one of the edition of 1,050 for sale at pounds 115.

It is one of only two ABC books in its stock. Collectable ABCs are scarce among dealers and auctioneers alike. Although dealers dominate the market, other children's book dealers I spoke to had no ABC books. Children are destructive.

But more are being published today than ever. A former graphics and typography lecturer, Dennis Hall, founder of the Hanborough Parrot press in Witney, Oxfordshire, publishes modern adult alphabets, some of them saucy. He has reprinted the Bertrand Russell alphabet. Two peeing men, 'Mind my feet' and 'No one's looking', in An Eighth Secret Alphabet (1988) by the 'life addict of surrealism' Tony Earnshaw, are from his press.

The ultimate lowdown on adult ABCs, also published by Hanborough Parrot, is David Blamires's beautifully illustrated Adults Alphabets (1990). His checklist of 56 titles includes A for 'Ackney, published by Lenthall Road Workshop in 1984, and an ABC fundraiser for Aids, Aiding and Abetting (1991), edited by John Byrne, with illustrations by 26 artists, hand-coloured at pounds 115. Hockney's Alphabet (1991), with the artist's letters accompanied by text from 26 authors, is also still selling, at pounds 175. Hardly books for kids.

Perhaps it is the childlike licence of the ABC format that has thrown up such colourful characters as the American Jerry Pallotta. The first biography of an alphabetographer, Chasing the Alphabet: the Story of Children's Author Jerry Pallotta, by Pamela Ryan (Shining Sea Press, dollars 5, 1993) says his 14 alphabets have sold more than 500,000 copies since 1986, and offers the amusing facts that he once harvested 2,420lb of sea moss in a day and took an elephant to his sister's wedding.

The illustrator, author and cult figure Edward Gorey, another American abecedarian, 6ft 5in tall, is revered by the New York City Ballet for his ability to sit through five performances in a weekend. His compilation, Amphigorey (G P Putnam's Sons, New York, 1972), is full of weird women in long gowns and men in wing collars, who live in a world of dark goings-on in which children had better watch out. It includes The Gorey Alphabet in which, 'The Proctor buys a pupil ices, / And hopes the boy will not resist / When he attempts to practise vices / Few people even know exist'.

Collectors tend to go either for the art or for the words (although all regard the choice of illustrations as what Mr Schiller calls 'a key to culture down the ages'). Mr Indictor is a wordsmith. His publishing company, Soggy Nook Books, sells limited-edition 'dramatic alphabet' books such as Adam and Eve Alphabetically ('Adam: Behold creation, dearest. Eve: Forget God. Hungry? . . .'), name alphabets and 'xenic, serious and irregular alphabets'.

The Newsletter's first alphabet challenge invited alphabets of words in which the first and last letters are the same, as in 'bib' and 'critic'. Since place names are considered a 'cop-out', readers had most bother with the letters A, J, Q, U, V and Z (Xerox was allowed). You are invited to supply solutions for the difficult letters. See? It's child's play.

N is for Newsletter and Soggy Nook Books (Nyr Indictor), PO Box 465, Chappaqua, New York 10514, USA. Dennis Hall, The Foundry, Church Hanborough, near Witney, Oxfordshire. Hockney's Alphabet ( pounds 3.75 p&p) and Aiding and Abetting (pounds 2.40 p&p) from John Byrne, Bertram Rota Ltd, 9-11 Langley Court, London WC2 (071-836 0723). Barbara Stone Rare Books (071-351 0963).

(Photographs omitted)