Medicine and religion cross paths in the examination of miracles and the canonization process of Roman Catholic saints. The author of this book, a medical historian and hematologist, compiles an impressive amount of data procured largely from four trips to the Vatican Secret Archives. She reviews 1,400 miracles from the time period 1588 to 1999 and discovers that 95% of these phenomena involve the healing of a physical illness. The author scrutinizes the nature of these miracles and investigates the dynamics and beneficiaries of them.

Medical expertise plays a central role in the substantiation of miracles. After all, miracles that involve healing imply a failure of medical treatment. Over the centuries, any physician providing testimony about the occurrence of a possible miracle must address two issues. The doctor must confirm the hopelessness of a patient's prognosis. The doctor must admit that the positive outcome of the case is nothing short of astonishing. The text is adorned by some splendid and strange paintings that illustrate people requesting or receiving miracles. It profiles celebrities in the history of the canonization process such as Prospero Lambertini (Pope Benedict XIV) and Paolo Zacchia.