The Pilbara and Yilgarn Cratons in Western Australia record the Earth’s early history from ca. 3.7 Ga to ca. 2.5 Ga. This paper highlights recent scientific work, and advances in understanding the similarity and differences in granitic rocks, greenstone stratigraphy, structural styles, and tectonic settings of the major granite–greenstone terranes within the cratons, and then discusses the crustal evolution trends from the Paleo- to Neoarchaean. We conclude that in the Pilbara and Yilgarn Cratons, the Paleoarchaean areas are characterized by vertical tectonics, whereas the Meso- to Neoarchaean areas are dominated by horizontal tectonics — plate tectonic processes may have started in the Mesoarchaean.