well.... that would be *in my opinion* of course but I'm pretty sure my children would agree.
They are both college age now but when they were little this was *THE* favorite bedtime story. The text weaves its way from city to country, describing the sights and sounds that you hear as the people and these places spend their days doing what country folk and city folk do before they drift off to sleep. The illustration are lovely, frame-able I'd say, and are so well detailed that the kids always loved to look for little things that are mentioned in the text - "look, there the pigeons are, mom!".
When they were *really* little I'd sometimes shorten the text, just reading a line or two and then the book has a feel to it like Goodnight Moon. By the time they were two years old they basically knew all the words by heart and I'd read the whole thing which makes for a long goodnight. It's a very relaxing story though and gives the children an effect much like when you ride in the car with them and they get sleepy.
My niece is due to have her first child in a month and that got me to thinking of the "bests" I had a a young mother; best toy, etc... that was what made me think of this book. Even twenty years later I remember this as *the best book*.