Short Story: Life-Line

Premise
A brilliant but contentious scientist builds a machine that can determine, with precise accuracy, the exact moment of a human being's death. The invention instantly becomes explosive: it promises undeniable knowledge about the single most private and final fact of life, and that promise collides with journalism, commerce, law, religion and government. The story traces the immediate human and social consequences of turning mortality into measurable data.

Plot summary
The narrative follows the inventor as he demonstrates his apparatus and negotiates its first public exposures. A skeptical editor, eager for a sensational scoop, and various representatives of business and state recognize both the profit and the peril in the new capability. Public demonstration and publication spread the device's results quickly, provoking a mixture of curiosity, opportunism and panic. People begin to confront the implications of knowing their own death dates, insurers and employers calculate new risks, and those in authority worry about the political fallout of such absolute knowledge.
As pressure mounts, official attempts to control or suppress the technology become central to the conflict. Legal and physical threats are weighed against the inventor's own convictions about truth and individual freedom. The story compresses the ethical debate into terse, often witty exchanges and a mounting sense of inevitability: a single breakthrough forces institutions to reveal their priorities. The plot builds toward a confrontation that tests whether knowledge that cannot be unlearned should be possessed, sold, hidden or regulated.

Themes and tone
Satire and skepticism run through the piece, with Heinlein treating institutions and professions, newspapers, courts, politicians, with a sharply comic, sometimes acerbic eye. The core ethical problem is simple but provocative: does the right to know one's fate trump the chaos that such knowledge might produce? The tale probes questions of free will, responsibility and how societies adapt when the private interior of life is made public. Rather than sentimentalizing mortality, the tone is brisk and pragmatic, using dialog and scenario to expose the absurdities and practical dilemmas that follow a revolutionary scientific claim.
Heinlein also examines the market instincts of a capitalist culture: once a technology produces usable information, there is an almost irresistible drive to monetize and institutionalize it. The story treats human reactions, greed, fear, curiosity, prudence, as predictable forces that shape moral outcomes as much as any philosophic argument. By keeping the pace fast and the moral stakes plainly drawn, the narrative forces readers to confront uncomfortable possibilities without moralizing.

Significance and legacy
Published at the dawn of Heinlein's long career, the story is a compact example of his preoccupations: technological speculation tied to social, legal and moral consequences. It established a formula that would recur in later work, an ingenious device or scientific insight upends ordinary life, revealing character and institutional priorities. The piece remains notable for its economy and clarity, delivering a provocative premise with sharp dialogue and a relentless focus on practical implications. Its influence is visible in later science fiction that treats prophecy, prediction and privacy as sites of social conflict, and it still reads as a lively, provocative meditation on how societies respond when private fate becomes public knowledge.