This talk was given at the 4th Annual Catholic Medical Association Medical Student and Resident Boot Camp held at St. Charles Borromeo Seminary in Wynnewood PA on June 22, 2016. I cover the following three topics, with most of the time spent on the third: 1. The Role of the Magisterium for Catholic Medical Professionals; 2. Object/Intention/Circumstances and the Hippocratic Oath; 3. The Nature and Dignity of Persons: Metaphysics of the Person. (Topic 3 is covered from a different angle than how I cover it in the 2018 talk of a similar title.