Who wrote the book of Kosmos?

The book "Cosmos" was written by Carl Sagan. "Cosmos" is a popular science book that explores the history of the universe, from the Big Bang to the present day. It was first published in 1980 and was accompanied by a 13-part television series of the same name hosted by Sagan. The book has been translated into more than 60 languages and has sold more than 70 million copies worldwide.