* New books are constantly released. The series is ongoing, so the count changes frequently.
* Different publishers and translations exist. There are different publishing houses for the series around the world, and some may have different titles or compilations.
* The series has multiple sub-series. Besides the main "Thea Stilton" series, there are spin-offs like "Thea Stilton & the Secret of the Fairies" and "Geronimo Stilton & Thea Stilton: Adventures Together."
However, you can find the number of books in the main Thea Stilton series by visiting the publisher's website or checking online databases like Goodreads.
Remember, the count will vary depending on what kind of books you're looking for (main series, sub-series, etc.) and where you're looking!