In this book cover image released by G. P. Putnam's Sons, "The Pope's Assassin," by Luis M. Rocha, is shown. (AP Photo/G. P. Putnam's Sons)

In this book cover image released by G. P. Putnam's Sons, "The Pope's Assassin," by Luis M. Rocha, is shown. (AP Photo/G. P. Putnam's Sons)