From the introduction:
The People of the Dust (Dusties) is a species of very small creatures, you could say microscopic - one of our buttons serves them as a door, or a shield.
They live hidden in the secret corners of our homes, in the nooks, in the attic, in the carpet, divided into clans and tribes, but we are rarely able to see them.
They look very similar to us... sort of.
Some are dressed in shavings, others in colored fabrics, others in leaves or skins; some look like 19th-century English gentlemen.