Helena Puumala's "The Summer Cottage Mystery" is Number 1 in the U.K. And Number 4 in the U.S.

Ok, it is just in the categories:

Childrens Books/Animals/Cats
and
Childrens Books/ Mysteries and Detectives/Detectives

But it is still cool.

 

Also doing nicely in Japan.  Well, it is the country that gave the world "Hello Kitty".

 

http://www.amazon.com/Summer-Cottage-Mystery-Childrens-Story-ebook/dp/B00N0B4TYY