Yesterday, the 23rd of April, was the day of Sant Jordi. Which is a very big day indeed in Catalonia, centred around a tradition that I find enchanting - that you should give a rose and a book to someone you love.

It's a beautiful thought - the rose encapsulates sensuality, and the book encapsulates dreams and visions and ideas. This symbolism is everywhere on the Diada de Sant Jordi, from the centre of Barcelona to the streets of the smallest town. As usual, first thing in the morning, I went to the swimming pool in Sant Pere, and at two out of the three roundabouts on the way there were people selling red roses out of plastic buckets ... in the changing room, sweaty men had carefully-wrapped single roses laid on the bench ready to take home to the wife (or - ?) ... and the little newspaper shop had a table outside piled with books, and yet more roses.

The classic is the single red rose, just opened, carefully wrapped in cellophane along with a single stalk of wheat for golden contrast, and all tied up with a ribbon of red and yellow stripes to suggest patriotically the Catalan flag. Our friends the Iraqi florists (living in exile for belonging to the Bahai faith) have just opened a new shop (see photo above), and were exploring all sorts of possibly heretical variations - whole bunches of yellow or white roses, strange bronze roses, even blue roses! They sensibly stuck to the patriotic angle - every heresy was safely tied up with red and yellow ribbon, and there were even glass flower pots with bands of red and yellow stones forming the base for the potted miniature rose.

The TV news has just announced that 5 million roses have been sold in one day in the whole of Catalonia. The going street price for a single wrapped rose is not less than 4 euros, and my red and white combination for my wife cost 8 euros, so imagine the turnover ...

But it's the book business that really benefits. In Barcelona, the Rambla de Catalunya is converted into a vast bookshop, swarming with people, among endless rows of kiosks and tents put up by every publisher and retailer in town. (Have a glance at El Pais' photographs.) There are huge queues of folk waiting to have their books signed by authors - who famously end up with writers cramp after scribbling their signature several hundred times. The association of Barcelona booksellers has just announced an early estimate of sales worth 10 million euros in Barcelona alone - a little up on last year, to everyone's relief, given worries about the recession.

Let's not get lost in the money side - what I find fascinating is that it is a huge celebration of the love of reading. The newspapers are full of supplements suggesting titles, and you hear people earnestly asking booksellers for advice. One of the many things that make this very Catalan tradition special is that it is all about buying a book that will give someone else pleasure - about choosing the right dream for a person you know and love.

Is 'dream' the best way of putting it? Apparently the best-selling title this Sant Jordi has been ¡Indignaos! by Stéphane Hessel - the furious polemic against cuts in social welfare policies following the financial crisis. [Have a look at the TLS review + available in English as Time for outrage! http://www.charlesglass.net/ ]