In this article, Christopher Tollefsen extrapolates the central contributions of the contemporary theory of natural law known as the New Natural Law Theory. With Aquinas as their starting point, the New Natural Law Theorists—principally Germain Grisez, Joseph Boyle and John Finnis—have formulated new articulations of natural law-thinking in the areas of moral thought and practical reason, human action, political authority, and teleology (or, the ultimate end of human beings). The New Natural Law Theory argues that practical reason (which directs human beings to certain actions) is capable of grasping as self-evidently desirable certain basic goods. These goods are enumerated as: life and health; knowledge and aesthetic experience; skilled work and play; friendship; marriage; harmony with God; and personal harmony or consistency in judgment, feeling, and action. It is in choosing to act for these basic goods that morality comes into play. For the New Natural Lawyers, the first principle of morality is that human agents ought to contribute to integral human well-being and flourishing and ought to avoid intentionally impeding or detracting from integral communal fulfillment. In order to accurately determine moral action, one necessary consideration is whether the person has acted with the intention to damage a basic good. Other important considerations include the fairness of accepting certain side effects that also damage basic goods. Acting morally is, for the New Natural Lawyers, as important for the individual person as for the well-being of the entire community. Hence, an understanding of the role of political authority and the end to which humans are aiming, both individually and collectively, is of central importance. Following the prescriptions of the first principle of morality, political authority is similarly enjoined to act for the integral well-being and flourishing of the people under its jurisdiction and to avoid intentionally impeding or detracting from integral communal fulfillment. It is the final realization of this integral communal fulfillment, in cooperation with the divine, that constitutes the ultimate end of human beings.