The Ends of the World provides a tour through Earth's five major mass extinctions, examining what they reveal about both planetary history and current climate change. Peter Brannen, a science journalist, travels to sites where evidence of these catastrophes remains visible—tropical rock in Siberia that was once at the equator, chalk cliffs built from the bodies of sea creatures—and interviews researchers reconstructing what happened. Each extinction had different proximate causes: asteroid impact, volcanic eruptions, ocean chemistry changes. But running through them is the role of rapid environmental change, particularly in atmospheric composition and global temperature. Brannen traces how scientists piece together evidence for events hundreds of millions of years ago while drawing connections to changes currently underway. He profiles the creatures that died and those that survived, showing how extinction reshapes the biosphere and opens opportunities for new forms of life. The book is not alarmist but sobering, showing that mass extinction is a recurring feature of Earth's history and that the changes humans are now causing bear disturbing resemblance to conditions that preceded past catastrophes. For readers interested in deep time, Earth history, and the current climate crisis's context, Brannen provides accessible and engaging science writing.