In the spirit of bringing into play the concrete contextualization alluded to in the book subtitle, the familiar medical procedure of skin grafting is invoked to suggest an instance in which the local and distant symmetries can be regarded as linear transformations. Thus, for example, a rectangular piece of skin harvested from the source tissue may have to be stretched and deformed into a parallelogram before grafting it at the target location. A review of elementary concepts in matrix algebra in two and three dimensions is undertaken. The general linear group and some of its important subgroups are defined for later use.