The Proterozoic and early Phanerozoic was a time punctuated by a series of significant events in Earth history. Glaciations of global scale wracked the planet, interfingered with dramatic changes in oceanic and atmospheric chemistry and marked changes in continental configuration. It was during these dynamic and 'weedy' times that metazoans first appeared, diversified, culminating in the appearance of hard tissue skeletons and deep 'farming' of the marine substrate, in late Proterozoic and first few millions of years of the Phanerozoic. This book is the culmination of two symposia of UNESCO International Geological Correlation Project 493, one in Prato (Italy) in 2004, the second in Kyoto (Japan) in 2006. Both dealt specifically with the precise timing of physical events and teasing out of the effects which these changing environments, climates, global chemistry and palaeogeography had on the development and diversification of animals, culminating in the spectacular Ediacaran/Vendian faunas of the late Precambrian.