The Four Diamonds is a fantasy themed, allegorical short story written by Chris Millard in 1972 shortly before succumbing to cancer at the age of 14. After returning from summer vacation, his teacher told Chris' class to write a story about what they did during their vacation. Chris had spent the summer being treated for his illness, and asked his teacher if he could write something else, to which she agreed. He wrote about adventures and struggle of an aspiring knight, also named Millard, to conquer Raptenahad (a play on "rhabdomyosarcoma," the cancer Chris had), a magic-wielding evil queen who symbolized his illness. To defeat her, the story's Millard has to complete four difficult tasks.

The story gave its name to the Four Diamonds Fund, a childhood cancer-centered charitable organization established in 1972 by Chris' parents Charles and Irma. The story was also turned into a Disney TV movie in 1995.