From Amazon:

Isasbel Dalhousie is a refined middle-aged lady philosopher who lives an elegant and tasteful life in Edinburgh. When she is at a concert, a young man falls to his death from the balcony above her. Isabel suspects that his death may not have been an accident or suicide, but murder, and she sets out to try and prove it. She is assisted by Jamie, her niece Cat's ex-boyfriend. Cat has
got a new boyfriend, a gorgeous hunk called Toby.....

(Note to self - ring to sarina79)