It was originally published as a novella with the same title in Isaac Asimov's Science Fiction Magazine and as a limited edition paperback by Axolotl Press in 1991.
The story revolves around the existence of the "Sleepless": individuals genetically modified to not need sleep, who have greater potential for intelligence and accomplishment than ordinary humans, called "Sleepers".
Yagai also founded "Yagaiism", a moral worldview Kress based on objectivism, in which dignity is solely the product of what a person can achieve through his or her own efforts, and the contract is the basis of society.
The novel's title comes from its primary moral question, as presented by character Tony Indivino: what do productive and responsible members of society owe the "beggars in Spain", the unproductive masses who have nothing to offer except need?
Nancy Kress has explained that the book, and the trilogy generally, grapples with the conflicting principles of Ayn Rand on one hand and Ursula K. Le Guin's picture of communist-like community on the other.
Tony is eventually jailed (for illegal actions on behalf of the Sleepless community), though not before attracting the attention of Jennifer Sharifi, the other person who makes Leisha nervous.
The Sleepless daughter of a movie star and an Arab oil tycoon, Jennifer's money purchases land in upstate New York (Cattaraugus County, specifically) to create a Sleepless-only community known as Sanctuary.
By sheer chance, Elizabeth conceived a natural daughter at the same time Leisha was implanted in vitro, resulting in fraternal twins, only one of whom is Sleepless.
On the drive home from the funeral, Leisha's surrogate mother Susan Melling (not only Roger Camden's second wife, but the genetic researcher who devised Sleeplessness) reports some startling news.
Leisha passes her exams, but shortly thereafter she is informed by Richard that various acts of prejudice and violence against Sleepless have culminated in the murder of Tony Indivino by fellow inmates.
Alice turns the tables by masterminding and almost singlehandedly carrying out the kidnapping, not only saving both Leisha and Stella but proving that even the most privileged and elite can be beggars too.
He shepherds his aunt Leisha on a tour of the factory; afterwards she meets with Hawke to "rail against stupidity;" since America is founded on the premise that all men should be treated equally, encouraging class hatred will only lead to destruction.
Leisha then receives an unusual client at her law firm: a genetic researcher, Dr. Adam Walcott, who claims to have discovered a post-partum gene therapy to turn Sleepers into Sleepless.
Fortunately, Alice comes to save the day, knowing (evidently through twin ESP) that her sister needs her; Stella confesses that the pendant is hers, which was stolen from her at a party; and Susan discovers that Walcott's research is a sham, completely infeasible.
He stole the pendant from Stella at a house-warming party Alice threw; he propagated the research, which he knew to be false, hoping that Sanctuary would react as it did; and, for reasons that remain unspecified, he had Walcott's assistant killed.
In Drew, the treatment backfires, and he gains access to a sort of genetic collective unconscious, which he perceives in visual terms (in the next book, in which Arlen is a first-person narrator, he constantly describes people, things, concepts and emotions as having shape, texture, color and so on).
Drew learns to project these shapes in holographic form and becomes the Lucid Dreamer, a performance artist who places his viewers in a waking dream, the contents of which are determined by the holograms.
Her genemods cause her brain to operate at three or four times the speed of a standard Sleepless, at the cost of muscle control (she and all the other Supers, including her brother Tony, twitch, jerk and vibrate with "manic vitality").
Within the first few years of Miri's life, it becomes clear that she and all the other Supers think differently than do normal Sleepless; their thoughts take the form of "strings," which are entire piles of data arranged in geometric shapes and involving analogy and cross-reference.
Miri flies into a rage when Jennifer reminds her of Sanctuary's Yagaiist, community-first philosophy, and must be sedated; when she wakes, she is told that Tony has died of his injuries.
The novel ends with Miri and the Superbrights moving to the Susan Melling Foundation complex in New Mexico, and Leisha deciding to act as the counsel for the defense in Jennifer Sharifi's trial.