The classic historical adventure series, with spies and the damsels who rescue them.
The term "series" applies loosely, as each book stands alone. In chronological order: Ask for It is the story of Marcus and Elizabeth. Christopher St. John plays a prominent role in their tale and his story is told in Passion for the Game, where you'll meet Amelia and Colin. Their story is told in A Passion for Him. Simon Quinn appears in both Passion for the Game and A Passion for Him. His story is told in Don't Tempt Me.
The Shadow Stalkers mini-series is a series of contemporary novellas following a group of special operations Deputy U.S. Marshals.
Urban fantasy written under the pseudonym S.J. Day. The Marked series follows the story of Evangeline Hollis: Cursed by God, hunted by demons, desired by Cain and Abel... All in a day's work.
The Renegade Angels series is a dark and sexy paranormal trilogy with several connected novellas, in which three factions—angels, lycans, and vampires—are all vying for power and supremacy.
Welcome to the Twilight—where dreams are real—as are Nightmares. Where Guardians fight with glaives against the darkness, protecting humanity from the shadowed enemy that feeds on their deepest fears. They’ve become phantasms, taking on the form and nuances of each individual subconscious they protect... The Dream Guardians® series is a true series, with an ongoing plot thread that follows through each book.
These titles are not part of a series but are connected.
Lucien Remington (hero of "Lucien's Gamble" in Scandalous Liaisons) is the proud owner of Remington's, an elite gentlemen's club. His establishment–and occasionally Lucien himself–can be found in most of my other Regency-set books. You can also catch his heroine, Julienne, in Catching Caroline. The Marquess of Fontaine first appears in "Lucien's Gamble". His story is told in "Mischief and the Marquess", which is in Perfect Kisses.
(Stories that do not appear in a series)