The title refers to a small museum that the four Moffat children set up to help them remember the special times in their lives now that they are growing up.

Rufus' teacher will be spending the summer in London, and she tells the class about the wax museum she plans on visiting while she's there.

Kirkus Reviews gave The Moffat Museum a starred review for ""books of remarkable merit", saying that "Estes has lost none of her feel for childhood's small, chance ecstasies--and the Moffats, have lost none of their small-town 1919 appeal… A notable series goes on undiminished--for a third generation of child-readers.

"[2] Taking note of the forty years between the previous book and this one, Anita Silvey says "the writing style proves the writer's ear was still well tuned to the language and thoughts of children".

Pointing out that the book doesn't leave out the difficulties a low-income family might experience at that time, Silvey also praises the sense of sadness some of the characters feel at the changes taking place.