With world population passing seven billion and predicted to hit nine billion by 2050, we are in the grip of a number panic. This book explodes some of the common myths, looks at what the numbers really mean, and addresses nine topics, such as why women in most parts of the world have fewer children, what will happen to our societies as we all live longer, and how having babies relates to climate change.

Vanessa Baird is co-editor at New Internationalist magazine. Her previous books include The No-Nonsense Guide to Sexual Diversity and, as compiler and editor, Eye to Eye Women.