The Duke's Men Books in Order

The Duke's Men series takes Jeffries's family plots and pushes them into full investigative adventure. At the center is Manton Investigations, an agency built around missing persons, hidden identities, and the sort of aristocratic scandals that respectable households would prefer buried forever. Dominick Manton and Lisette Bonnaud help drive that world, but the cases quickly widen into a larger network of siblings, half siblings, and old lies.

It is Jeffries with more mystery in the engine.

What the Duke Desires sets the tone well. A duke looking for a vanished brother collides with Lisette, whose own brother has disappeared, and the search forces them into a dangerous partnership. From there, books like When the Rogue Returns, How the Scoundrel Seduces, and If the Viscount Falls keep mixing romance with investigations, old wounds, and family revelations. Related shorter pieces such as Dorinda and the Doctor add a side glance at characters orbiting the same world.

What makes this series feel distinct from the earlier school or sibling cycles is movement. The plots send people across borders, into disguise, through false leads, and toward truths that can damage whole families. Yet the books still keep romance at the center. The investigations matter because they strip away social performance. Once people are on the run, pretending to be married, chasing a witness, or prying open a scandal, they have less room to lie about what they feel.

The tone is brisk and slightly more suspenseful than some of Jeffries's other series, but not cold. She still likes wounded heroes, shrewd heroines, and extended family complications. She just lets them solve a case while they are at it.

If you enjoy historical romance that borrows some energy from thrillers and detective stories, this series is a very good fit. Read it for the romance if you want, but the connected secrets make it especially rewarding in order.