In the latter part of the nineteenth century, G. K. Gilbert began a study of the origin of the lakeshore features of ancestral Lake Bonneville. By means of hypothesis and observation, he used features of the shorelines of the Great Lakes and the Atlantic and Pacific Oceans to form modern-ancient analogs. Studies of present coastal processes and the geometry and internal structure of the Lake Bonneville shorelines lead to the hypothesis that the littoral transport mechanism was dominant in the formation of lagoon-barrier coastal systems. His works on barrier evolution have stood the test of time. Although some of the world’s barrier shorelines have evolved by other processes, most of them appear to fit Gilbert’s hypothesis for barrier evolution. Furthermore, the process of littoral transport appears to be of great importance in modification or alteration of coastal barrier landforms no matter what their origin.