This study is organized around three themes: the origin and early diversification of life during the Archean Eon; the maturation of life and the Earth during the long Proterozoic Eon; and the explosive diversification of multicellular life that marks the dawn of the Phanerozoic Eon. The contributors discuss the coherence of history, the combinatorial generation of taxonomic diversity, early Metazoan evolution, and the Cambrian explosion.