It was inspired by a real life experience, when the author's young son, Walter, was disturbed by losing his first tooth.
Convinced that he is falling apart and will soon become toothless, skinless, brainless, and bald, the boy tries to hold himself together with his father's masking tape until he resembles a mummy.
Imagining that these expressions could lead to his body falling apart (his central preoccupation in Parts), Chip invents various kinds of protection for himself.
Chip has compiled a list of all the worrying and mystifying things he has heard from adults, and makes himself a suit of armour to protect him while he is at school.
The illustrations often feature minor characters from the previous books – Chip's toy superhero, dinosaur and tank.