James Patterson is a prolific author who has written numerous series and standalone novels throughout his career. To date, he has written over 200 books, which have sold over 375 million copies worldwide.
Patterson is best known for his crime and thriller novels, many of which are part of ongoing series. Some of his most popular series include the Alex Cross series, the Women's Murder Club series, the Michael Bennett series, the Private series, and the NYPD Red series. He has also written several young adult series, including the Maximum Ride, Witch and Wizard, and Middle School series.
To give a more precise answer to the question, James Patterson has written over 25 different series, with many of them comprising multiple books. The Alex Cross series, for example, has 28 books, while the Women's Murder Club series has 20 books. Other popular series like the Michael Bennett and Private series have also been ongoing for several years and have numerous books in each.
In addition to his series works, Patterson has also written many standalone novels and co-authored several books with other writers, such as Candice Fox and Bill Clinton. His novels have been translated into over 50 languages and adapted into films, television shows, and audiobooks.
Overall, James Patterson's body of work is vast and varied, with something for every reader to enjoy. His ability to craft thrilling and suspenseful stories has made him one of the most successful authors of our time.