Silent Craftsman

In a desperate mood after being unfairly fired from a job that he held for thirty years, Ev Stone stole a book from the office of Rudy Ruggins, his ex-boss. Ruggins pursued Ev in the hope of retrieving his book, tipping off Ev that it probably was very valuable. Ev left the country --- only to be followed by Ruggins. The book contained a secret that motivated Ruggins to hire unsavory characters to burglarize Ev's house, to beat him with chains, and finally to attempt to murder Ev. What mystery could drive people to commit such desperate crimes?