A term with numerous applications, including a legal one in the United States (as designated by the U.S. Public Land Survey system), range in its strictest, yet most abstract, sense means the outer demarcations between which variation is possible, or the difference between the highest and lowest values in any series. Hence, a mountain range is deﬁned by its location, geologic character, and origin, and anything that occurs within that compass, however varied, is a part of the range. More than one distinct range may occur in close proximity to another, as with the Rocky and Big Horn Mountains, and the Wind River Range in Wyoming. A second, equally important application of the term is to the territory within which a creature, such as a cougar, or a species, or a group within a species, may reside, journey, and ﬁnd sustenance. Domestic livestock, such as cattle, have ranges assigned to them. The ranges of all animals— and of ﬂora, as well—interface in complex, mutually dependent ways, as suggested by John McPhee in Basin and Range: “The range of the cougar is the cougar’s natural state, overlying tens of thousands of other states.” There is also Annie Proulx’s playful title Close Range.