Stewart's engrossing sixth Kopp Sisters novel (after 2019's Kopp Sisters on the March) finds the three siblings, based on actual sisters, separated for the first time, though they keep in touch through letters written from May to December 1918. Constance, the first female undersheriff in the U.S., remains home in New Jersey ferreting out German saboteurs. Fleurette travels across the country entertaining the troops with May Ward and Her Eight Dresden Dolls, a real-life vaudeville act. Norma, who's stationed in a French village behind the front, trains carrier pigeons to relay military messages for the Army Signal Corps. (The travails of the pigeon service are a source of ongoing humor.) Meanwhile, a nurse serving with Norma at the American Field hospital becomes involved in the case of the theft of medical supplies. The nurse enlists Norma's help, which may be connected to a spy ring. The tension rises as the 1918 flu pandemic looms large and events move closer to Armistice Day. Readers will eagerly await the sisters' postwar adventures. (Jan.)

Following the LJ-starred Kopp Sisters on the March, this new series entry finds the redoubtable siblings separated for the first time by World War I. As Constance hunts spies on the Continent, Fleurette sings and dances her heart out for the troops, and Norma lets her pigeon project for the Army Signal Corps go winging while helping a nurse wrongly accused of stealing medical supplies. With a 25,000-copy paperback and 3,000-copy hardcover first printing.

Stewart's popular series takes an epistolary turn as the Kopp sisters chronicle their separate World War I adventures via letters. This requires some authorial contrivance. Norma, established as a woman of few words in the previous five volumes, has to have her terse missives supplemented by the chatty epistles of her friend Aggie, a nurse at the American hospital in France where Norma is battling military indifference to her cherished pigeon messenger program. Fleurette's escapades in the chorus of a revue performing for troops in U.S. Army camps are recounted mostly to a nonjudgmental friend rather than her anxious older sisters. And Constance's reports on tracking down spies are so improbably novelistic that Stewart feels obliged to have her justify them as ways "to better paint a picture" for her superior at the Bureau of Investigation. Readers will not mind a bit, as the series returns to top form after a spell of doldrums in Kopp Sisters on the March (2019). Two mysteries drive the plot: An unjust accusation that Aggie is stealing hospital supplies launches Norma into an investigation that ultimately nabs a German agent; and Constance tracks down a ring of saboteurs in New Jersey with the help of Fleurette, who has done some growing up on tour while caring for a green parrot entrusted to her by a soldier heading overseas. As always, the feisty sisters refuse to be daunted by men who doubt their abilities or, in Fleurette's case, the ladies of the Committee on Protective Work for Girls who are sure that young women's interactions with soldiers "weaken their morals and inflict upon them crippling social diseases." The censorious committee really existed, as did the Army's pigeon program, but Stewart acknowledges in her endnotes that she has invented more of the Kopps' activities than usual due to a lack of information about their WWI years. No matter: The fictional opportunities she dangles for her three feisty protagonists at the novel's close will leave readers eager for the next installment. Smart, fun, staunchly feminist entertainment. Copyright (c) Kirkus Reviews, used with permission.