Book decorations are illustrations that surround text and are meant to subtly portray themes in the writing as well as be aesthetically appealing. Margaret Armstrong’s designs most often feature floral motifs that border the page. The Miriam Irwin Collection of Margaret Armstrong Book Design has several books that have Armstrong’s decorations within.

Pippa Passes (1900) by Robert Browning is Armstrong’s most notable decoration work with illustrations surrounding each written passage. The designs are comprised of black illustrations printed on a pale yellow block which makes the designs stand out from the white page. Pippa Passes features nine repeating borders and twenty-nine non repeating full page borders