According to Investopedia , the following are the ten best-selling book series of all time, showcasing the incredible impact these stories have had on readers worldwide.

Harry Potter by J.K. Rowling (500 million copies)

The magical journey of Harry Potter and his friends at Hogwarts School of Witchcraft and Wizardry has enchanted readers of all ages. The series includes seven books, starting with "Harry Potter and the Sorcerer's Stone" and concluding with "Harry Potter and the Deathly Hallows".

Goosebumps by R.L. Stine (350 million copies)

This horror series for children features standalone stories that often end with a twist. The original series consists of 62 books, beginning with "Welcome to Dead House".

Perry Mason by Erle Stanley Gardner (300 million)

This detective novel series, which includes 82 novels, has been a go-to in the literary world since it was first published in 1933. It features the fictional defence attorney Perry Mason.

Berenstain Bears by Stan and Jan Berenstain (260 million copies)

This children's series follows the everyday adventures of a family of anthropomorphic bears. The series began in 1962 with "The Big Honey Hunt".

Choose Your Own Adventure by various authors (250 million copies)

Known for its interactive format, this series allows readers to make choices that affect the story's outcome. The series includes numerous titles, including "The Cave of Time".