Fat Ollie's Book - Ed McBain

Irritating though he was, Lester Henderson had it all when he strode up to rehearse his keynote address in the darkness of a downtown theatre. Widely tipped to be next mayor and possessing a nice line in catalogue-casual daywear, Henderson stood four-square facing his glorious future. But five shots later and his lifeblood was seeping away - gunned down by persons unknown from stage-right...
At that point he became Ollie Weeks' problem. But this savage crime is suddenly overshadowed by a deed even more repugnant. Ollie's life work is his novel. Honed by countless rejection letters, it is finally ready to be released to the general populace. But then the one and only manuscript disappears, leaving Ollie to head off in pursuit of the thief. a thief who is convinced that Ollie's work contains the secret location of a hoard of hidden diamonds...