Book excerpt: Ancient ice ages are revealed by distinctive stratal facies that tell us much about the times of coolness and how the climate system works. Several strong ice ages were recorded in the late Paleozic time and during transitions from the Devonian in to the Carboniferous and from the Ordovician in to the Silurian. In Precambrian time, several are documented for both the late and early Proterozoic age. This title explores findings on the pre-Mesozoic ice ages, examining climate in relation to tectonobiogeochemical activities rooted in the changing earth-air-ocean system.