It was a hive of activity in the basement of the Oxfam book shop in St Giles the other day, when I dropped in for a spot of volunteer valuation work.

Staff at the shop are all looking forward to this weekend's 21st birthday celebrations.

Space on the shelves in the basement office is at a premium because donations of new books are coming in all the time, so my first task was to try to work my way through a stack of needlecraft and quilting books which were taking up rather a lot of room.

I grabbed about 20, pricing most of them at about £4.99, but then I got distracted by a pile of PG Wodehouse novels, which I hoped would provide a little bit of light relief.

I didn't have to wait long. The first Wodehouse in my bookstack was Enter Psmith and bingo, it was an A&C Black first edition with green boards and no dust jacket from 1935. With the dust jacket Oxfam would have been looking at a cool £70, but without I was forced to opt for a more conservative price of £19.99.

Enter Psmith turned out to be the pick of the bunch in financial terms. Love Among The Chickens by the same author, published by Herbert Jenkins, was priced at a mere £4.99 because one of the previous owners had taped up the spine, immediately knocking pounds off the value.

Then there were presentable copies of The Indiscretions of Archie, Nothing Serious, Money in the Bank and Joy in the Morning.

After a second session with the knitting books - there are still quite a few left to be priced - I found another gem.

It was The Wonderful Wizard of Oz by L Frank Baum, illustrated by Biro.The Dent Dutton edition from the mid-1960s was beautifully illustrated but not a first edition so it was priced at £9.99.

Throughout the morning, I kept glancing over at a book on the desk of my colleague Doreen, who never misses a valuation trick.

The Brighton Road by Charles G. Harper, published by Chapman and Hall in 1906, was being advertised for sale on abebooks, I think. Or was it being auctioned on eBay?

I nearly saved Doreen the bother because the book, about my old stomping ground on the South Coast, was full of plates and illustrations and I was tempted to make an offer there and then.

But the book is worth about £30, so I thought I would buckle down instead to a bit more needlework.

After a few hours in the bunker, I left Oxfam and made my way down St Giles, to Cornmarket, and turned right into St Michael Street, where I went into Arcadia and bought le Carre's The Night Manager for £2.50.

That, Gerald Martin's biography of Gabriel Garcia Marquez, and an old Paul Theroux train travelogue, should keep me extremely busy.