This book covers the history of climate for the last 600 million years. Part of the book is a summary of palaeoclimate information for different slices of geologic time. We believe it is necessary to update and attempt to synthesize the great body of research on palaeoclimates generated over the last ten years or so. But there was a further purpose in the collection of these basic data and that was to establish a framework which we could use to compare and contrast similar climate states of the past, and from there to recognize some causes of climate change. We have divided climate history into Warm Modes and Cool Modes, in a way not unlike Fischer's (1982) ‘Greenhouse’ and Icehouse' states, but our Modes are of shorter duration and contain some controversial elements – we have questioned the theory that the Mesozoic climates were uniformally warm and ice free and instead propose a Cool Mode in the middle Mesozoic. We have also included a chapter on the climates throughout the Quaternary, something which is often missing or abbreviated in texts on geologic climates, not surprisingly considering the huge volume and the increased scale of detailed information available for such a relatively short time.