Yet another classic of children's literature that I didn't discover until adulthood. But this one, I really liked. It inhabits that fictional Edwardian period I love so much, with many of the modern conveniences, and none of the annoyances. Also, in British literature, as in American film and TV, you get adults who don't really work.
The story opens with Mole getting fed up with his Spring cleaning, so he wanders off, and meets up with Rat and they live happily ever after. Pretty much. They have some adventures, and some very eccentric acquaintances, but mostly they just hang out on the river, messing about with boats in the good weather, and sit at home snug by the fire in bad weather.
Interesting observation: there don't seem to be any female animals. There is a female human, crucial to a bit of plot, but otherwise nothing. Perhaps the females are off providing the many essential services, such as making food, for these gentlemen to live.
Mole and Ratty don't seem to read a lot of books, but otherwise, they lead an idyllic, lazy existence, rather like Mr. Tumnus first met out shopping in a country without any stores or shop keepers. Lovely.