Deadly Daggers by Joyce and Jim Lavene.*
The third of the Lavenes' Renaiassance Faire Mysteries (after Wicked Weaves and Ghastly Glass) has doctoral student Jessie Morton apprenticing at Swords and Such, home of the Village's swordmaster Daisy Reynolds.
The start of Jessie's apprenticeship is delayed a bit, however, because famous swordsman Alastair is visiting for a demonstration, and has challenged Daisy to a duel. Once Jessie meets Alastair, she's pretty sure Daisy will win, but protocol says she must not.
Daisy, it turns out, once had a tempestuous relationship with Alastair, and has no intention of losing. After the duel, Alastair blood-soaked corpse is found in his bed, and Daisy becomes the chief suspect.
Jessie is certain that Daisy is not guilty, and since her boyfirend, Village bailiff Chase Manhattan doesn't seem to agree, she decides it's up to her to convince the police of Daisy's innocence, with many mishaps ensuing.
For the uninitiated, Jessie's dissertation is called "Proliferation of Renaissance Crafts in Modern Times", and her research involves spending each summer with a different craftsmith at Faire. Ignoring the fact that this means her dissertation could take years and years to finish, this is a great premise for a series.
The Lavenes have done a great job describing what life might be like at a permanent Renaissance Faire theme park while skilfuly creating an enjoyable mystery.
*Full disclosure: I received a review copy of the book from the publisher.