The Shaper/Mechanist universe is the setting for a series of science fiction short stories (and the novel Schismatrix) written by the author Bruce Sterling. The stories combined cover approximately 350 years of future history, for the period ranging from AD 2200–2550. (Note: All years given are taken from "A Shaper/Mechanist Chronology" in the book Schismatrix Plus, which includes all the Shaper/Mechanist material.)

The stories deal with a posthuman society spread across the solar system—primarily in fragile orbiting colonies around planetary bodies like the Moon, Jupiter, Saturn and the Sun. The Earth and its inhabitants have been abandoned by these citizens of the so-called Schismatrix, and no communication is performed or attempted with them. Humanity has largely polarized into two competing factions:

The Shapers attempt to push the limits by manipulating the human body itself, through genetic modification and highly specialized psychological training. The Shapers are aristocratic, placing heavy emphasis on "gene-lines"—to be "unplanned" (i.e., born) is considered a serious disadvantage. Their methods could best be described as "organic". Shaper society, based around the Military-Academic complex, is described as fascist.

In contrast, the Mechanists have disdain for the Shapers' methods and instead prefer to use cybernetic augmentation, advanced computer software, technical expertise, and drugs to achieve their goals. The "Lobsters" are Mechanists who permanently seal their bodies into life-support shells allowing them to live and work in deep space. Some Mechanists even go as far as to become "wireheads"—individuals with no corporeal body who are simply manifested as computer simulations. The Mechanist philosophy favors individualism more than the collectivist Shapers.

This uneasy duality is transformed and complicated by the arrival of the Investors, lizardlike aliens that trade with both factions (who consequently compete for the aliens' favor).

One recurring theme in the Shaper/Mechanist universe is that of the commodification of humanity. Both Shapers and Mechanists often treat individuals as if they were technology—subject to ownership, control, obsolescence, etc. There is a continual tension between people attempting to express their individuality and human feelings, and the political, economic and technological forces that compel them to suppress their humanity.