Which author wrote the 'Mary Russell' series?

Laurie R. King wrote the Mary Russell series.

The Mary Russell books follow a highly intelligent young woman who becomes the apprentice, colleague and eventually wife of a retired Sherlock Holmes. Mary first meets Holmes in Sussex in 1915, when she is fifteen and he is living in the countryside as a beekeeper. Their relationship develops into a partnership that combines her modern perspective with his famous investigative methods.

The series begins with The Beekeeper’s Apprentice, published in 1994. Although Sherlock Holmes is central to the premise, the books are Mary’s story rather than conventional Holmes pastiches. King presents many of them as memoirs written by an older Mary Russell, creating a layered fictional-documentary style.

The stories range across Britain and locations including Palestine, India, Japan, France and Morocco. Anne Perry, Deborah Crombie and Charles Todd are also associated with historical or traditional mystery fiction, but Laurie R. King created Mary Russell and her distinctive continuation of the Holmes world.