The element of change and the effect it has on human society is a persistent theme in Leiber's fiction, and he is one of the few science-fiction writers of his generation to consistently stay abreast of the cultural changes around him. Leiber, above all, has been aware that change—or evolution—is not only inevitable, but necessary to human growth. It is a theme that is most obvious in his Change War stories, but it can be found in subtler forms throughout his fiction. (pp. 13-14)

Gather, Darkness takes place in the far future on Earth, with a group called the Hierarchy holding sway over the commoners. The religion they have formed is a corrupted form of Roman Catholicism, with a structure reminiscent of Dante's Inferno. The priesthood is defined by a series of circles, with the outermost circle being the first, and the whole governed by the...