Janusz Grabianski (1929-1976) was a polish illustrator specialised in children's books. He used a bold and expressive watercolour and/or gouache technique in his artwork.
He illustrated the 1001 nights, the Holy Bible, the Andersen and Grimm tales, quite a few other children stories, and many more books.
If you have the opportunity to find a reissue or an used copy, don't doubt it: it's very enjoyable.
These are some articles about Grabianski on the net: