Katherine Kurtz, born in 1944, is an American writer recognized for her contributions to fantasy literature, particularly her Deryni series. Her work often blends historical settings with fantastical elements, distinguishing itself from traditional mythology-based fantasy. Kurtz has also explored occult and urban fantasy genres. She lived in Ireland for over two decades before relocating to Virginia in 2007. Her academic background includes degrees in chemistry and medieval history, which she pursued while also working in law enforcement and other fields before dedicating herself to writing.

Her debut novel, Deryni Rising (1970), is noted for its approach to fantasy, drawing more on historical fiction conventions. Critics have highlighted her detailed attention to the role of faith in pre-modern societies and her depiction of magic as a structured, ritualistic practice. Beyond the Deryni series, Kurtz has penned occult alternate history novels within her Templar series and urban fantasy stories in her Adept series. She maintains an active connection with her readership through regular online interactions.

Katherine Kurtz is celebrated for pioneering a style of fantasy that closely resembles historical fiction. Her Deryni series, beginning with "Deryni Rising" in 1970, broke from the prevalent mythological or legendary approaches common in high fantasy at the time. This distinct method involved a deep focus on the importance of faith and religious structures within pre-modern Western societies. Furthermore, Kurtz portrays magic not as an arbitrary force, but as a formal, ritualistic practice, setting her work apart from more informal or picaresque depictions of magic found in contemporary fantasy literature. This innovative approach has led to her being described as a foundational figure in secondary-world historical fantasy.

While best known for the Deryni novels, Katherine Kurtz has also delved into other speculative fiction subgenres. Her bibliography includes works within the occult and urban fantasy realms. Specifically, she authored the Templar series, which explores occult themes within an alternate history framework, and the Adept series, focusing on urban fantasy narratives. These diverse explorations showcase her versatility as a writer, allowing her to apply her meticulous world-building and character development to a variety of fantastical settings and concepts beyond her acclaimed Deryni universe.

Born in Florida in 1944, Katherine Kurtz pursued a varied academic path, earning a B.S. in chemistry from the University of Miami and an M.A. in Medieval History from UCLA. Her early professional life included experiences in law enforcement, oceanography, and television before she focused on writing. Kurtz lived in Ireland for over two decades, becoming a naturalized Irish citizen along with her husband, Scott MacMillan. They resided in County Wicklow until 2007, when they moved back to the United States, settling in Virginia. Her husband, who worked in the film industry and later served as a herald, passed away in 2019.