Many leading intellectuals agree that the risk of human extinction this century may be higher than at any point in our 300,000-year history as a species. This book provides insight on the key questions that inform this discussion, including when humans began to worry about their own extinction and how the debate has changed over time. It establishes a new theoretical foundation for thinking about the ethics of our extinction, arguing that extinction would be very bad under most circumstances, although the outcome might be, on balance, good. Throughout the book, graphs, tables, and images further illustrate how human choices and attitudes about extinction have evolved in Western history. In its thorough examination of humanity’s past, this book also provides a starting point for understanding our future. Although accessible enough to be read by undergraduates, contains new and thought-provoking research that will benefit even established academic philosophers and historians.