Aisling Grey, Guardian Books in Order

Aisling Grey, Guardian is one of the series that helped define Katie MacAlister's dragon world. It starts with a simple enough setup: Aisling is a courier from Seattle on a job in Paris. She is supposed to deliver a valuable object and get on with her life. Instead, she stumbles into murder, dragons, demon summoning, and the kind of revelation that makes returning to normal impossible.

She also meets Drake Vireo.

That matters because the Aisling books are powered by two things at once. One is the romance between Aisling and Drake, a green dragon leader who is arrogant, dangerous, and very sure of what he wants. The other is Aisling's own discovery that she is far more than she thought, including a Guardian with responsibilities tied to the Otherworld. Those threads keep pulling her into bigger trouble with every book.

Aisling is the reason the series works so well. She is funny, stubborn, overwhelmed, and determined in equal measure. She keeps finding corpses, keeps landing in the middle of magical politics, and keeps reacting like a person who did not remotely consent to this level of nonsense. That human response gives the books their comic heartbeat.

Then there is Jim, the demon in Newfoundland form, who becomes one of the great scene-stealers in MacAlister's universe. Between Jim's commentary, Drake's intensity, and Aisling's constant effort to survive one more impossible day, the books balance romance and chaos with real ease.

If you want an entry point into the dragon side of MacAlister's fiction, this is still one of the best places to start. The series has mystery, magic, dragons, demons, travel, and a heroine who keeps discovering that the universe has assigned her a much stranger job than she ever applied for.