The Nome Trilogy (or the Bromeliad Trilogy, as it is sometimes called) is ostensibly a trio of books for children, but frankly, it can be read with great enjoyment by adults as well. As with the best of animated films, the bits for the adults and the bits for the kids are interweaved so successfully that it's difficult to think how they could have been un-interweaved.
The three books are Truckers, Diggers, and Wings.
Truckers introduces the readers to Masklin and Grimma, two young nomes, and a few older nomes, who have spent all their lives out "in the open" where the 4 inch high human-looking creatures struggle to survive against foxes that eat them, food that won't grow, and so on.
The Nomes live in a faster time than the humans do... the humans are slow moving, unintelligible, but probably intelligent.
Masklin arranges for his small band of nomes to hide away on a truck, which brings them to.... the Store. Arnold Brothers, established 1905. There are nomes there...nomes who have lived there all their lives and regard the Store as their entire world, with various gods (Bargains Galore, a godlike figure just below Arnold Bros (1905) and a devilish figure also known as Prices Slashed) and their own religious caste (the Stationeri).
The Outside nomes have brought with them the Thing, a small box which comes to life when it is held near electricity, and turns out to be the small computer from a crashed spaceship. The nomes's ancestors came from outer space, their scout ship had crashed on earth over a hundred years ago ago...and the mother ship remains in orbit waiting for the nomes to return so it can take them home.
But the Store nomes don't believe this of course. Still less do they believe the Thing's news (it can communicate with the computers in the store) that the Store is closing and will be demolished.
It's up to Masklin to save the day, and the 2,000 nomes in the Store - in a hilarious and thought provoking tale that all will enjoy.