THE BLACK BOOK by Ian Rankin (1993)

There are several black books that give this gripping Rebus tale its title. When a close colleague is brutally attacked, Detective Rebus is drawn into a cold case that involves a hotel fire, the privileged playboy son of a banker, an unidentified corpse and a long forgotten night of terror and murder. HIs nemesis Ger Cafferty figures slyly. Rebus has to try to decode the secrets in his colleague's notebook to piece together a jigsaw of clues that no-one wants completed.