Kolkata: Describing books as a person”s best friend, West Bengal Chief Minister Mamata Banerjee today urged people to cultivate a reading habit as it is good for the mind. “Today is World Book and Copyright Day. Books are a person’s best friend. They open up our minds. We must work together to preserve the reading habit,” Banerjee tweeted this morning.World Book Day or World Book and Copyright Day is an annual event to promote reading, publishing and copyright.It is organised by the United Nations Educational, Scientific and Cultural Organisation.