The Black Book (Inspector Rebus #5) by Ian Rankin

Five years ago, a mysterious fire burned Edinburgh's seed Central Hotel to ashes. Long-forgotten and unsolved, the case reappears when a charred body--with a bullet in its head--is found amongst the ruins. Inspector John Rebus knows that his superiors would rather he let sleeping dogs lie. He knows that part of the answer lies somewhere in a cryptic black notebook. And he knows that to solve the case, he'll have to peel back layer upon layer of unspeakable secrets to arrive at the truth. . .