It was disappointing. In the past, they've had lines of tables laden with books, packed so closely it's hard to walk past anyone browsing, with boxes of other books underneath ready to be brought out to replenish stocks. This time, there were fewer lines of tables and walking between them was easy; there were no replenishment stocks of books beneath the tables, just someone who came in with new books everyso often to fill spaces by hand. There were more people partaking of the tea, coffee and cake than there were looking at the books. Also, they used to have a section containing very old books, but not any more; my guess is that if anyone gives them an old book, they sell it to a book dealer rather than let it go to the book fair.
As for why it's in decline, well I saw books on airbrushing (useless post-Photoshop) and genealogy (not the same in 1988 as it is now); I saw film directories (like imdb.com but less comprehensive), four complete sets of the Encyclopaedia Britannica (like Wikipedia but bulkier), over forty dictionaries (like a word processor's spell-checker except it doesn't look up every word automatically); I saw four boxes of books on trains (because the old people who owned them and were interested in steam engines have died); I saw How to Use Windows XP in among a dozen books explaining how to set up my own web site.
It's not just the reference works that are no longer in demand. There's a lot of fiction, but why pay £1 for a second-hand book when you can get it for 99p on your Kindle?
We did get two books, anyway. One was an identify-those-strange-mushrooms-growing-in-your-garden book, which my wife bought so she could identify the strange mushrooms growing in our garden. The other was The Mote in God's Eye, which I've been meaning to read for close on 40 years; I bought it to reward the NSPCC for reminding me about it. If the pages are too icky, I'll get it on the Kindle, too.
The award for the most racist book cover this time round goes to From Slum to Quarter-Deck, published 100 years ago in 1915:
The award for best title goes to Old Men Forget, which I wrote down in my notebook just in case.