Marie and Pierre Curie, discoverers of radium, were the husband-and-wife team responsible for pioneering discoveries about radioactivity. These celebrity scientists are background characters in the book, but their fame is one of the drivers of the “radium mania” of the early-20th century.

Grace Fryer

An intelligent, politically inclined young woman from Orange who joins the suit with Katherine, Albina, Quinta, and Edna.

Katherine Schaub

An imaginative, sociable dial-painter from Newark who begins work at 14. She aspired to be a writer.

Albina Maggia

Sister to Mollie and Quinta. A devoted dial-painter from an Italian family.

Mollie Maggia

A social and friendly dial-painter. She was one of the first dial-painters to die, and her autopsy later provided valuable evidence of the effects of radium poisoning.

Quinta Maggia

A down-to-earth and friendly dial-painter close with Grace Fryer. She married James McDonald and they had several children before her death.

Edna Hussman

A religious, kind dial-painter who loved music. 

Sabin von Sochocky

The Austrian-born doctor was the founder of USRC and inventor of Undark paint.

Arthur Roeder

A highly successful businessman who moved from treasurer to president of USRC.

Clarence B. Lee

A vice president of USRC.

Edwin Leman

The chief chemist who died of radium poisoning.

George Willis

USRC’s cofounder, with Sabin von Sochocky.

Harold Viedt

A vice president of USRC.