How Olaf Stapledon and other writers use imagination to test futures before evidence can reach them. Here optimism is a faculty, not a forecast.

The statistical case that human life has improved, followed by the harder question of what the figures leave out. A chart can correct the news without settling the argument.

How progress changed from a hope into an argument, and the people who made it one. Optimism did not arrive by weather.

A tour of futures confidently promised and futures that arrived without being predicted. Invention has a better record than prophecy.