It was first published as a trade paperback by Ace Books in 1979, by the first UK edition in hardcover by Sidgwick & Jackson Ltd the following year.

Merlin will need to modify his Spider to extrude pure silicon cables, and to work in space.

As work progresses, Merlin becomes convinced that his parents' accidental deaths, when he was a child, were in fact murders.

[3] This novel was published almost simultaneously with The Fountains of Paradise by Arthur C. Clarke.

Both protagonists are engineers who have built the world's longest bridge using a machine named the "Spider", both of whom are hired to build a space elevator, and both engineers modify their Spiders to produce a crystalline fiber.