The Law of Life is a term coined by author Farley Mowat in his 1952 book People of the Deer, and popularized by Daniel Quinn, to denote a universal system of various natural principles, any of which tend to best foster life—in other words, any of which best guides behavior that tends toward the reproductive success and survival of some particular gene pool. The idea posits that, in general, the most fit organisms instinctively behave according to some natural rule (often, these rules vary among and are specific to the species). Since every organism has some instinctive "law" it can follow to be the most reproductively successful, this very notion is a sort of law itself, true of all living beings: thus, the Law of Life.