Great book for book loving kids

This was a random free eBook I thought sounded interesting, and funny, just based on the title. And it was indeed fun and very clever.

The conceit is that 3 kids find a secret room in a bookshop (owned by one of the girls' uncle) in which they are whisked off onto an adventure according to the book they first pick up.

This story integrates Hansel and Gretel but with a twist!