Priest catchers were professional lawmen in the Era of the Underground Church in England (1535-1679). They raided houses where they suspected a Mass was being held, guarded the ports where newly ordained priests might land, searched the houses of known Catholics for the secret panels which disguised the "priest holes." The stories of 40 of their victims, who were declared saints in 1970, are told in this book. They included not only priests, but those who helped them, like the butcher's wife, St. Margaret Clitherow, pressed to death in 1586, and the mysterious carpenter, St. Nicholas Owen, who designed priest holes so cleverly that some of them were not discovered until the 20th century. Among the martyred priests were the great poets St. Edmund Campion and St. Robert Southwell.
Pretty good book on some of the martyrs of the English Reformation and State persecution of Catholics. Not at all objective in it's depiction of Martyr/Persecutor, but I don't believe any book of history, much less martyrology can be anything but subjective. In the dust cover there is a quote from Paul IV from their canonization ceremony "These martyrs take us back to those turbulent times when the Christian family was torn apart. Yet their canonization should not reopen old wounds. On the contrary, it should offer us a signal opportunity humbly to confess our own faults and to ask pardon for them." There are some familiar names like Edmund Campion, Margaret Ward, and Thomas More, but also a lot of people who I had never heard of before. They were all martyrs in the most literal sense of the word, "Witnesses."