The fatal flaw of most utopian visions is that they're fundamentally static, and that's not a comfortable place for humans to live. Fourier was very good at imagining a utopia that is constantly changing and very busy, but a vision of paradise that would have been most tantalizing to an underfed overworked factory worker in 1840 doesn't have much appeal in fiction because it's not a story.

So there's that change of general consciousness, and then there's this boom after the war, this expansion into the West. It was like the 1950s. The American economy was pumping at top speed. The kinds of people who would move into these communities and organize their lives around a utopian dream now had dreams about the West.

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 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.

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?