The story is aimed at 4-7 year-olds. It was inspired by a real life experience, when the author's young son, Walter, was disturbed by losing his first tooth. The protagonist of Parts is young Chip Block, who notices that some of his hairs remain on his comb, lint is appearing in his navel, his skin is peeling, and a piece of mucus falls out of his nose. His anxiety reaches its peak when he discovers one of his teeth is coming loose. 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. Finding him wrapped in the masking tape, his parents then explain to him about how parts of his body renew themselves.
Sequels
''More Parts''
This sequel to Parts was first published in 2001. Like its predecessor, the story is aimed at 4-7 year olds, written in rhyme and illustrated by the author. Chip from Parts now becomes frightened by his literal interpretation of the idiomatic expressions involving body parts that he hears adults using. Imagining that these expressions could lead to his body falling apart, Chip invents various kinds of protection for himself. For example, when his father asks him "to give a hand", he glues gloves to his hands to keep them from coming off his arms. Other expressions covered in the story include:
"It’s sure to crack you up."
"Stretch your legs."
"Hold your tongue."
"Scream your lungs out."
''Even More Parts''
This final book in Arnold's trilogy was published in 2004, and is again illustrated by him. Unlike its two predecessors, Even More Partsis not, strictly speaking, a narrative and is not written in rhyme. Aimed at children 4-8, it is an introduction to the use of idioms or figures of speech in language, and more specifically to the use of idioms involving body parts. The protagonist is Chip from the first two books of the series, his name is revealed as - Chip. 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 remainder of the book is an illustrated list of the sayings that have puzzled him. For example, one page shows the students' eyeballs flying out of the children's eye sockets hitting the teacher when she says, "I want all eyes on me." The illustrations often feature minor characters from the previous books - Chip's toy superhero, dinosaur and tank.