Strict tradition states that on 23 April, the Diada de Sant Jordi, or St George's Day, men give roses to their loved ones and the women respond by presenting their beloved a book. But this tradition has evolved along with society, and nowadays people are likely to give or receive either or both of these gifts.

On this day, Barcelona fills up with all kinds of bookstalls. Many streets and squares are taken over by bookshops which add a cultural level to the celebrations. The Rambla is the hub of the festival. Early in the morning, the booksellers set up their tables and fill them with books. Throughout the day, people arrive in their droves, to look for the book they want. One of the best moments is when authors sign their new books surrounded by readers eager to get their hands on a signed copy.

Although the tradition of giving roses is very old, the gift of a book is quite recent. The event was first held on 7 October,1926, and throughout Spain, at the suggestion of the Valencian Vicent Clavel to the Cambra Oficial del Llibre de Barcelona. But in 1930 it was changed to Sant Jordi's Day. The festival died out in the rest of Spain but became more and more important in Catalonia, where it began to acquire an air of national assertion and defence of the language.

The celebration was moved to 23 April for commemorative reasons: this is the date on which the writers Miguel de Cervantes and William Shakespeare died. The same day also marks the birth or death of other globally-known writers, such as Josep Pla (1981), Maurice Druon (1918), K. Laxness (1902), Vladimir Nabokov (1899) and Manuel Mejía Vallejo (1923).

In 1995, UNESCO declared 23 April World Book and Copyright Day.