THE wording on young Callum's party invitations is explicit: ''You are invited to a BIG PARTY. Dress Scottish.'' After such an opening you might read on with trepidation Tom Pow's first children's book, Callum's Big Day (lynx Publishing #5.99). It could so easily be some terrible tartan pastiche. Certainly the national icons are spread across the pages as thickly as overcooked porridge: from the feathery, thistle-strewn endpapers to the Jimmy wig in the final spread, it's all there - the kilt, a Scottie dog (name of Taggart), both national drinks, Burns, a claymore, Nessie, a heilan' coo etc etc. But Pow and illustrator Mairi Hedderwick approach their subject with such wit and zest that this potential MacBore is a wee gem.

The story charts Callum's ambition to be ''a real Scotsman'', even if his kilt is too big and his long ginger beard is knitted by his granny. Despite his family's scepticism, Callum dances the Highland Fling, insists on the Selkirk Grace, and dreams of helping Bonnie Prince Charlie send the Redcoats packing at Culloden.

The book ends with an exuberant hooley in which every guest pitches in with their particular take on Scottishness. The cast includes Willie Wallace, Mary Queen of Scots, a human haggis, and a cameo appearance from Hedderwick's own literary offspring, Katie Morag. The book is targeted at the five plus age group but, thanks to the lightly comic text and Hedderwick's many non-verbal jokes, will have strong appeal to many older children and adults, especially Nats and ex-pats.

''The idea for Callum came from my son Cameron. About two years ago when he was seven, he became desperately interested in all things Scottish. Braveheart probably started it but it spread out from there. He began finding out about Robert the Bruce, William Wallace, and Rob Roy, and how people lived,'' says Pow.

''At school he formed a group with two friends and they called themselves 'the Highlanders.' The teacher gave them free rein. He was quick to pick up on issues. 'Why is it wrong to say Aye?' he asked me one day. Around this time he found out that he wasn't actually fully Scottish - my wife is Irish - so the whole idea of identity became a much more shifting arena for him.''

Pow, aged 50, has published poetry with Canongate and Bloodaxe, dabbled in travel writing, and lectures in creative writing and cultural studies at Glasgow University's Crichton Campus in Dumfries. He was recently ''Virtual Writer in Residence'' for the Lottery-funded Scottish Writers Project organised by the Scottish Library Association.

Callum's Big Day is his first children's book. A decade ago, he doubts if he could have got away with the theme. Scots were too prickly about national identity. There was a self-consciousness and a bitterness. Culloden still grated. ''Now we can take these things a lot more lightly. We've all got lots of different identities and parts of identity. I see this book coming out of a confident post-Devolution Scotland where we can wear our kilts any way we want, where you can wear a baseball cap the wrong way round and still feel Scottish.'' The depiction of Scottishness is deliberately inclusive. Li, Rashid, and Jasveer are all invited to Callum's party. Hedderwick consulted representatives of Scotland's ethnic minority communities before tackling the final spread to find out how they would respond to the ''Dress Scottish'' invitation. ''We wanted something they would feel completely comfortable

with,'' says Pow.

From the start he had Hedderwick in mind as the illustrator: ''I've always admired her work. She peoples things so well. I saw it as a single figure kind of book but she's created a whole cast of characters, including two cats and a dog who feature throughout the story, even though they never appear in the text.

''We both knew the tone we wanted. She gave a lot of thought to the image we should project. When Callum finally gets his gear on and goes off to his do, she was very insistent that he shouldn't be in any way ridiculous.''

Hedderwick was also keen to take the book to a Scottish publisher and at the Wigtown Book Festival last September introduced Pow to Tom and Liz Short of the small Aberdour-based Lynx Publishing. They loved the idea immediately and a year later Callum's Big Day was launched at this year's Festival.

Two other newly-published picture books look at Scotland through entirely different

lenses. Michael Morpurgo's The Silver Swan (Doubleday #10.99) has a haunting, elegiac quality that left my tender-hearted seven-year-old crying himself to sleep. The story of a dying swan on a Scottish loch is inspired by Orlando Gibbons's idea of the swan song and based loosely on an experience of the son of well-known Scottish children's author and illustrator, Debi Gliori.

A boy watches a pair of swans build a nest on an island in a loch and rear a brood. As winter grips the countryside, life in the animal kingdom is reduced to a desperate struggle for survival. A fox needs food for her young and when the loch freezes, the swans are in terrible danger.

Purists quibble with Christian Birmingham's photo-based pastel technique but there's no denying that he has caught beautifully the mood and colour of a deep-frozen Scottish landscape. And after the grimness of the story, the final spread, as the bereaved cob meets a new mate amid a golden sunset, is suitably uplifting.

The traditional Scottish tale of Tam Lin inspired authors and composers alike, including Eddie Stiven and Sally Beamish. The Enchanted Forest is an inspirational reworking of the story by Rosalind Kerven, with magically atmospheric watercolour illustrations by Alan Marks. It's now out in paperback from Frances Lincoln (#5.99).

Janna is ''a wild sort of girl'' who dares to enter an enchanted forest where she meets Tam Lin, whose grey eyes smoulder with strange, secret mists. He has been enslaved by the Queen of the Fairies.

To free him, Janna must undergo a series of terrible trials. It's a powerful tale of love and courage, or, put another way, a dead spooky read for Hallowe'en. Marks uses elongation and perspective to heighten the sense of menace. Tam O'Shanter would

benefit from similar treatment.

n Tom Pow and Mairi Hedderwick will be signing copies of Callum's Big Day at Borders Bookstore in Glasgow next Saturday at 11.30am.