The book's introduction provides extensive background material on the families and distortions of map projections. Each projection begins with a helpful description of the usage and context for that specific projection.

Prior to presenting the mathematical formulas necessary to calculate the projection, Snyder first goes into great length regarding the aspects, usage, and history of the subject.

The U.S. Geological Survey (USGS) now employs several of the more popular projections for its published maps, after employing the Polyconic for decades as its exclusive map projection for its mapping program. Conformal projections like the Transverse Mercator and the Lambert Conformal Conic are used for larger-scale maps, such as topographic quadrangles and the State Base Map Series. The National Atlas includes projections with equal-area and equidistant boundaries. Occasionally, for practical reasons, different projections are adopted, such as the Miller Cylindrical and the Van der Grinten, sometimes using pre-made base maps. Other projections treat the Earth as either an ellipsoid or a sphere, while some only treat it as a sphere.

The USGS has also developed a number of novel map projections, notably the Space Oblique Mercator, the first projection to allow low-distortion continuous mapping of the Earth from space. The mapping of extraterrestrial bodies has led to the application of conventional projections in hitherto unimagined contexts.

The cartographic community is frequently interested in a number of different projections that the USGS has not adopted. It is crucial to understand that, with increased computerization, rectangular coordinates for all of these projections can be mathematically calculated using formulas that, in the past, would have seemed too complex to be programmed routinely, but which are now possible, especially if helped by numerical examples.

There is an explanation of each projection's appearance, usage, and history, as well as both forward and inverse equations.