Poul Anderson 
Murder in Black Letter 

What can a precious pre-Renaissance manuscript, a 600-year-old treatise on witchcraft and black magic, have to do with the violent death of a quiet, friendly young teacher of history at the University of California?

This is the question that Robert Kintyre asks himself when his friend, Bruce Lombardi, a colleague on the Berkeley campus and a man seemingly without enemies, is found murdered, bearing the marks of horrible tortures. Kintyre is a Renaissance scholar, a specialist on Machiavelli and an expert at judo—and murder is more than a little out of his line. But he is convinced that the medieval Book of Witches is somehow connected with the crime. When the girl he loves is in danger of becoming the murderer’s next victim, Kintyre knows he has to act fast to track down a ruthless killer.

And when a lone man goes down to a beach in the fog to fight three armed men—the result is a terrifying blend of suspense and mystery.