Jostein Gaarder is a Norwegian writer who is famous worldwide thanks to his famous novel, "Sophie's World" or "Dunia Sophie" in Indonesian. Born on August 8, 1952 in Oslo, Norway, Gaarder has written more than 15 books, including novels, children's stories, and nonfiction books.

Gaarder began his career as a teacher of philosophy and literature, but is best known for his work as a fiction writer. "Sophie's World" is her most famous work and has been translated into more than 60 languages. This book is a philosophical novel that takes the reader on an exciting journey of the history of Western philosophy, presented in the form of a fictional story about a teenage girl named Sophie.

Other notable works include "The Solitaire Mystery" and "The Christmas Mystery", both of which are children's novels with elements of mystery and adventure. Gaarder also wrote many books on philosophy, including "Through a Glass, Darkly" and "The Castle in the Pyrenees".

Gaarder's works often contain elements of philosophy, mystery, and metaphysics, as well as themes of love, life, and human existence. Many of his works also discuss human relations with nature, religion, and beliefs. His works are often praised for inviting readers to think and reflect, and provide a deeper understanding of the meaning of life and our existence in this world.