Gregor the Overlander by Suzanne Collins (2003)

I wanted to check out other things by Suzanne Collins, as I loved her Hunger Games. Gregor and his baby sister Boots fall through a hole in the laundry room into an underground world populated by humans, roaches, bats, rats, and spiders, though all the animals are human sized and do not all play well together. Gregor is asked to take up a quest, which he does. I liked the world that Collins created, though the character was a bit young for me (12). I am not sure I will look up the rest of these books, but listening to one was fine.