The vision shared by both [French utopian] Charles Fourier and Robert Owen was for an entire town to fit into one structure. Owen's design for what he called a "parallelogram" was essentially to have a whole city in one building, laid out around a huge quadrangle. Fourier's scheme was to build a massive Versailles-like structure that he called a "phalanstery." In both cases they had these architectural dreams that we now recognize as pretty unappealing.

The secular utopians basically said the exact same thing, they just took the Bible out of the equation. The religious and the secular groups recognized each other as fellow travellers. They exchanged newsletters and asked each other questions like, "What's a good soup pot to use if you're making dinner for 800 people?" They had these practical connections.

They [Oneida people] didn't want to fix problems one at a time. If someone invited them to a feminist convention, their answer would have been, 'In the new world women will have total equality, so lets spend our energy creating that whole new world.' And to their credit, the women at Oneida probably had far greater practical equality than what any of the women gathered at Seneca Falls experienced in their lifetimes.

Some people just think utopians are idiots who are imagining rivers of candy and not really engaging with the world's ills, and sometimes that's surely the case, but I think that imagining the perfected society is a way of expressing your disgust with the current state of affairs.

The Jacksonian era is generally talked about in terms of individualism, and the development of free market capitalism, and Victorian prudery. It was shocking to find a parallel history to that - a bunch of Americans with very different priorities. I stumbled on to these people, and then became completely fixated on them. The question that drove me was: how did these reasonable people adopt these extremely unreasonable ideas?

The thought was, 'We're going to go to California, where the soil is black and ten feet deep, and there are no rocks, and there's gold in the hills.' The West becomes the surface onto which people project their fantasies, where once the future had been the place they projected their fantasies. So it's not just the war that ends the utopian communities, but what follows.

That to me was one of the most exciting, and weird puzzles of this book: how are the most religious people and the least religious people of their time all drawn to very similar visions of utopia?