Few books have made me see the world in such a different way as this brilliant work by Criado Pérez which exposes a historical and continuing inequity – if our decisions are (increasingly) made using data, and if data around women is not only under-collected but more often than not it is simply not collected: an omission that begins to look deliberate in its scale. This has disastrous consequences for human health, happiness, productivity, and welfare. And it’s simply not good enough and we must do better: collect data and challenge the male as default bias.