In 1958, which surprise hit was the first foreign-language book on the New York Times Best Seller list?

"Winnie ille Pu" became a New York bestseller in 1958. Alexander Lenard translated the children's story "Winnie-the-Pooh" into Latin. His inspiration came from using the book "Winnie-the-Pooh" to teach Italian children Engish and thought it would be great to teach English speakers Latin the same way. He had to self-publish the book initially as publishing houses were understandably skeptical of the book's potential. After the book's success, other children's stories were translated into Latin and other languages to use as teaching tools.

https://en.wikipedia.org/wiki/Winnie_ille_Pu