The Concept of Physical Law is an original and creative defense of the Regularity theory of physical law, the concept that physical laws are nothing more than descriptions of whatever universal truths happen to be instanced in nature. Professor Swartz clearly identifies and analyzes the arguments and intuitions of the opposing Necessitarian theory, and argues that the standard objection to the Regularity theory turns on a mistaken view of what Regularists mean by 'physical impossibility'; that it is impossible to construct an empirical test that can distinguish between events Necessitarians call 'mere accidents' and those they call 'nornologically necessary', and that the Necessitarian theory cannot account for human beings' free wills. Other topics in this important work include: the distinction between instrumental scientific laws and true physical laws; the distinction between failure and doom; potentialities; miracles and marvels; predictability and uniformity; statistical and numerical laws; and necessity-in-praxis.