Here's why:
* No Central Database: There is no single, comprehensive database that tracks book sales across all publishers and time periods.
* Multiple Editions & Translations: The book has been reprinted countless times in various editions, from classic hardcovers to modern paperback versions, and translated into numerous languages.
* E-books and Digital Sales: Sales figures are further complicated by the advent of e-books and digital platforms, which don't always have easily accessible sales statistics.
However, it is safe to say that "The Wind in the Willows" is a beloved classic that has sold millions of copies worldwide. It remains incredibly popular today and is frequently adapted for stage and screen.