On Earth, catastrophic impact of an asteroid or comet with truly global consequences has not happened during our written history, and the threat seems very small. Giant scars on our planet's surface are relics of an impact history stretching back more than 2 billion years, and there is no assurance it cannot happen again. In Australia there are 36 structures ranging from tens of metres to tens of kilometres in diameter, and recognised to varying degrees of certainty as having been formed by giant meteorite impact. In clear and concise language this book begins with ancient beliefs and myths about craters and then explains how they are actually formed and provides details of their structure. Using the record in the rocks, the authors also assess the likelihood of future impacts and their possible effects.