The story of Lynne Truss's enormous success with her punctuation primer Eats, Shoots & Leaves is too well known to need repeating. That it made her a very wealthy woman inspires no jealousy in me; I am the last to resent the financial success of any of my fellow hacks, though I would prefer not to have to restate that with a lie-detector in place. Seriously, I rejoice at someone other than that endless parade of TV chefs, style gurus and 'celebrity' slappers being able to bank a shedful. Lynne is clearly enjoying herself: with a nice line in self-deprecating wit, she recently told readers of the Daily Telegraph that her literary success had made her address "familiar to every asses' milk delivery company in the land" (and please note the placing of the apostrophe in asses, for a reason I shall come to in a minute).

But there is someone who appears to be niggled by Lynne's success - and I suppose with good reason. David Crystal is - so the back-cover blurb on The Fight for English tells us - "the foremost writer and lecturer on the English language, with a worldwide reputation and over a hundred books to his name". Over a hundred! That's some going. What must it be like to see a Jeannie-come-lately all but corner the market in his subject, trousering millions, while he has had to make to with an OBE? Little asses' milk bought with that, I fear.

Crystal worked as advisor to Lynne on Cutting A Dash, her series of four Radio 4 programmes that was a forerunner to Eats, Shoots & Leaves. He tells us in the prologue to The Fight For English that "her approach was delightful, the right blend of serious interest and quirky thinking". But when a book was suggested, he told her: "I wouldn't bother. Books on punctuation never sell." I suppose what he meant was that his books never sell. But then he isn't a moderately attractive blonde with lots and lots of friends in the media to help in the plugging operation. OK, Lynne is saddled with an unattractive surname, which calls to mind a surgical appliance or a tied-up turkey, though no one but me seems to notice that.

I hope lots of people bought copies of The Fight For English (Oxford University Press, £9.99) last weekend when its author addressed literary enthusiasts in the Town Hall as part of the splendid Woodstock Celebrates Books festival. It is, you see, a very enjoyable book and makes a case well worth making. The nub of Crystal's argument is that the "zero-tolerance approach to punctuation", which Lynne deems so important, is flawed since it takes no account of context in assessing the meaning of what has been written.

He gives a good example of this concerning the observation by one critic - from that home of pedantry, The New Yorker, needless to say - that Lynne had herself made an error in the dedication on the first page of her book. It reads: "To the memory of the striking Bolshevik printers of St Petersburg who, in 1905, demanded to be paid the same rate for punctuation marks as for letters, and thereby directly precipitated the first Russian Revolution. Here I might pause to ask whether 'striking' couldn't in this context first appear to mean 'attracting attention because of unusual or impressive qualities'?

The critic argued that a comma was required between 'St Petersburg' and 'who' because without it Truss was dedicating her work to "those printers who demanded to be paid" and suggesting there were others who did not demand to be paid. This had clearly not been her intention. "Do you see the fundamental reason for the difficulty?" Crystal asks. "The two commas surrounding 'in 1905' are there to express the sound effect of this part of the sentence. The comma after 'printers' is there to express a grammatical contrast. We need all three if we want to do both. But if we put all three in then suddenly the sentence starts to look cluttered." He concludes: "All Lynne had to say to the New Yorker pedant is that the meaning of her dedication is clear from the context."

Finally, a couple of questions. Though I have been scratching my head about it, I fail to see any ambiguity - as broadcaster John Humphreys and David Crystal both do - in the sentence: "Surrounded by barbed wire, armed soldiers guarded the prisoners from watchtowers." Surely the writer meant that the armed soldiers were surrounded by barbed wire. Why should it be rewritten to "Armed soldiers in watchtowers guarded the prisoners, who were surrounded by barbed wire"?

Second - and this relates to the aforementioned asses' milk - should it be greengrocer's apostrophe or greengrocers' apostrophe? I ask because Lynne appears to think it's the former and Crystal the latter. I confess I often find myself confused about this when writing about such things as livers (calf's or calves'?). But why not calf liver, as in chicken liver? Anybody help, please?