Notes

24 p. : col. ill., maps. Quick read. Cover title. Table of contents: Fossils rock -- Mass death -- Germs? Gases? Great Hunger? Gamma rays? -- Wicked weather -- Death from the sky -- Past and future. Summary: "Much of the life on Earth was wiped out six different times in the planet's history. What caused these mass extinctions? Explore one of Earth's biggest mysteries and consider the question, could it happen again?"--Back cover.