What is the most popular book series of all time? What factors make it so popular? What lessons or values does it convey to its readers?The Harry Potter series is the best selling book series of all time. It has sold over 500 million copies and has been translated into over 80 languages. The series follows the adventures of a young wizard, Harry Potter, as he learns to use magic and battle dark forces. The series is popular for its vivid characters, exciting plot, and its underlying message of friendship, courage, and determination. It has inspired many readers to pursue their dreams and face their fears.