Journeying backwards in time from the most recent Ice Age to the dawn of complex life itself, palaeontologist Thomas Halliday immerses us in sixteen lost ecosystems, each one rendered with a novelist's eye for detail and drama. Every description - whether the colour of a beetle's shell, the shambling rhythm of pterosaurs in flight or the lingering smell of sulphur in the air - is grounded in fact. An epic, exhilarating journey into deep time, showing us the Earth as it used to exist.