This text describes the evidence for how life moved from sea to land, beginning more than 400 million years ago, employing the concept of Hypersea which is the idea that the barren land surfaces of the Earth could only have been colonized by multicellular organisms working in concert.

The authors explore the late Precambrian and earliest Cambrian fossil record to explain the Cambrian phenomenon and discuss the possibility of a major turnover in marine ecology at the beginning of the Cambrian period or whether a new, improved type of animal appeared at this time. They support their often controversial conclusions with photos and illustrations of fossils, some never before published.