[1] Originally subtitled "A New Scientific Romance", it has been seen as an early steampunk novel,[2] dealing with an alternative British Imperial history dominated by airships and futuristic warfare.

The story of Oswald Bastable's adventures "trapped forever in the shifting tides of time" is framed with the concept of the book being a long lost manuscript, as related by Moorcock's grandfather.

By contrast, South Africa, rechristened Bantustan, is ruled by President Mohandas Gandhi, has never had apartheid, and is an oasis of civilisation which stayed out of the conflict being an affluent, technologically advanced nation in this alternate, anti-imperialist twentieth century.

To restore civilisation and social order in the afflicted Northern Hemisphere, a 'Black Attila', General Cicero Hood, leads an African army to beneficent if paternalist conquest of Europe and an apocalyptic war against the United States featuring the "vast, moving ziggurat of destruction" of the title.

[3] They are contrasted with the impoverished, tribalised white supremacists of the devastated former United States, which has reintroduced African American slavery.