Lasting memories of Harold Hare's Garden Party

A favourite book when a young child was Harold Hare's Garden Party - long lost, and which I had not seen for more than fifty years until a found a few images on a (now defunct) website. 

I can immediately see why the this made such a lasting impression on me, because the illustrations are marvelous; containing just that kind of humorous and fascinating background detail that brings a child back to the book again-and-again. 

This kind of illustration is the child's equivalent to the seriousness and self-consistency of 'world building' that some adults enjoy and appreciate among the best High Fantasy writers.