Let’s celebrate the opening of Loncon, the great exhibition of science-fiction fandom, in London tomorrow. SF is one of the leading art forms of the modern world, and fandom invented the future quite as much as the writers did. In the works of outstanding science-fiction writers, we see how to face and understand the worlds that are emerging in a time of constant change. In the workings of fandom we understand how to create imagined communities. Fans imagined their own community into existence long before the internet made it easy for anyone to do so. Many of them felt like permanent misfits. They were fractious, opinionated and quarrelsome. Yet they worked out the rules and rituals that make it possible to flourish together. The close links between readers and writers, united by a common sense of wonder and imagination, were a gift to both sides – and ultimately to the rest of us as well. Let them flourish till the galaxies grow cold.