Three Golden Keys by Peter Sis

Sometimes librarians don't know where to put art books so they put them in the young reader section. I would not call this a children's book, although the dedication in the front says that the author is addressing the book to his daughter, Madeleine. It is more of a mystical tribute to the City of Prague. His illustrations remind me of M. C. Escher or Joann Sfar. The book style is reminiscent of Graham Baese's 11th Hour or Where the Wild Things Are by Maurice Sendak. In an interview with Sis, the author does say that he was influenced by Sendak and that Sendak played a part in introducing Sis to New York book publishing .
I would not recommend this book to children, but I would to young adults that are into manga or adults planning a trip to the Czech republic or adults with Czech ancestors.

Trivia for Ohioans From Sixth Book of Junior Authors and Illustrators entry on Peter Sis:
"My mother's father designed railway stations in Cleveland and Chicago in the 1930s, and my mother lived in the United States as a little girl".