The Devil's Queen is about the infamous Catherine de Medici, who became Queen of France in 1547 when her husband, Henri II, succeeded to the throne. She held varying degrees of influence during the reigns of three of her sons. It's known that she employed an astrologer, Cosimo Ruggieri, and consulted the seer Nostradamus. Historians disagree over the extent of her responsibility for the assassinations of Huguenot leaders which set off the St. Bartholomew's Day Massacre. Enlarging on the facts of Catherine's life, Kalogridis spins a tale with a darkly supernatural deed at its heart.

The first quarter of the novel musters sympathy for Catherine by imagining her childhood in extensive detail: the tumult in Florence during the war between supporters and opponents of the Medici, her mistreatment in a convent, and her use as a political pawn in the European marriage market. Young Ruggieri is introduced early as her secret protector, as sinister as he is reassuring. Catherine, who has horrifying dreams she believes are prophetic, begins to study astrology on her own and finds it offers little comfort. "Mars, hot red warrior, was conjunct Saturn, harbinger of death and destruction, and passing through my ascendant - Leo, the marker of royalty. . . . And Saturn, silent and dark, had sailed into my Eighth House, the House of Death."

Married at fourteen, Catherine quickly falls in love with Prince Henri, despite his coolness to her and his attachment to his deportment tutor, Diane de Poitiers. But when Catherine's womb stubbornly refuses to quicken, she resorts to magic of a particularly dark sort. Later, Nostradamus says ominously, "These children should not be."

Though not fast-paced, the novel is punctuated by sensational scenes and dramatically symbolic passages. Liquids, from wine to water to tears, typically bleed rather than drip or pour. The Devil's Queen is for those who enjoy a romanticized story of glittering but dangerous court life, laced with a recurring frisson of horror. (2010; 470 pages, including an Afterword about the history behind the story)