|World Book Day|
UNESCO World Book and Copyright Day 2012 poster
|Official name||National World Book Day|
|Observed by||All UN Member States|
World Book Day, also known as World Book and Copyright Day, or International Day of the Book, is an annual event organized by the United Nations Educational, Scientific and Cultural Organization (UNESCO) to promote reading, publishing, and copyright. World Book Day was first celebrated on 23 April 1995, and continues to be recognized on that day. A related event in the United Kingdom and Ireland is observed in March.
The original idea was of the Valencian writer Vicente Clavel Andrés as a way to honour the author Miguel de Cervantes, first on 7 October, his birth date, then on 23 April, his death date. In 1995 UNESCO decided that the World Book and Copyright Day would be celebrated on 23 April, as the date is also the anniversary of the death of William Shakespeare and Inca Garcilaso de la Vega, as well as that of the birth or death of several other prominent authors. (In a historical coincidence, Shakespeare and Cervantes died on the same date -- 23 April 1616 -- but not on the same day, as at the time, Spain used the Gregorian calendar and England used the Julian calendar; Shakespeare actually died 10 days after Cervantes died, on 3 May of the Gregorian calendar).
In Catalonia, Spain, St. George's Day (Diada de Sant Jordi), the Saint Patron of this historical region, has been commemorated since 1436, and involves the exchange of gifts between loved ones and respected people. St George's Day in Catalonia is celebrated with giving loved people Books and Roses, and is an opportunity for Catalans to honour their patron saint and show their love of culture 
In Sweden, the day is known as Världsbokdagen ("World Book Day") and the copyright aspect is seldom mentioned. Normally celebrated on 23 April, it was moved to 13 April in the year 2000 and 2011 to avoid a clash with Easter.
In the United Kingdom and Ireland, World Book Day is a charity event in March, held annually on the first Thursday and coinciding with the release of special editions. The annual celebration on 23 April is World Book Night, an event organized by independent charity The Reading Agency.
Tunisian students perform reading on the street, on the 2012 World Book Day
Book fair in Helsinki, Finland on World Book Day 2011
"5-minute reading" campaign (rather, the 5-minute reading content just printed one sheet of paper) at ?ód?, Poland in 2013