A child of the English Age of Reason learns lessons of the heart in McMahon's fifth historical, her first published in the U.S. Like Philippa Gregory, she mixes historical accuracy with a heroine modern at heart if not in outward appearance. It's 1727, and 19-year-old Emilie Selden, cloistered since birth at Buckinghamshire's Selden Manor, is docile under the iron rule of her domineering father, John, a scientist by reputation and an alchemist by calling. Under his stern tutelage, Emilie, who narrates, studies nature using the same methods used by their hero, Sir Isaac Newton. While on the verge of formulating her own theory of air and fire, Emilie meets two men: Thomas Shales, a clergyman and natural philosopher who alienates John Selden as much through his regard for Emilie as through his disregard for alchemy, and Robert Aislabie, a London adventurer who calls at Selden Manor to gain the father's secrets and ends up taking the daughter's heart. Father and daughter soon learn that love and loss cannot be kept in the confines of the laboratory. McMahon highlights social turmoil through Emilie's maid, Sarah, and intellectual conflict at the Royal Society, including a memorable evocation of Newton's funeral. Emilie's voice is clear, and McMahon doesn't shy away from the Enlightenment's darker sides, giving this popular historical a satisfying gravity.