[3] Caps for Sale is a popular read-aloud book, because its repetitive text permits children to speak the lines and thus join in the reading experience.

[5] "According to the following relation from a person just returned from the Labrador coast, the imitative faculty in monkeys seems to exceed every thing short of human — A sailor having a number of red woolen caps and care to dispose of among the natives, went on shore for that purpose; his way to a settlement lying through a woods very copiously inhabited by the species mentioned above, and it being midday, put a cap on his head, and laying the others by his side, he determined upon a little repose under the shade of a plantain tree.

To his utter astonishment, when he awoke, from the specimen he had given his imitative observers of the use of his caps, he beheld a number of them upon the heads of the monkeys on the trees, round about him, while the wearers were chattering in an unusual manner.

Slobodkina published a sequel, Pezzo the Peddler and the Circus Elephant, in 1967, twenty-seven years after the publication of Caps for Sale.

[7] A direct sequel bringing back the monkeys, More Caps for Sale, was published in 2015, credited jointly to Slobodkina and her long-time personal assistant Ann Marie Mulhearn Sayer.