Stanley Lloyd Miller (March 7, 1930 – May 20, 2007) was an American chemist who made important experiments concerning the origin of life by demonstrating that a wide range of vital organic compounds can be synthesized by fairly simple chemical processes from inorganic substances.

The experiment was widely reported, and provided evidence for the idea that the chemical evolution of the early Earth had caused the natural synthesis of organic compounds from inanimate inorganic molecules.

He searched frantically for a thesis topic, met professors, and preferred theoretical problems rather than experiments, which tended to be laborious.

"[7] The Miller experiment was described in his technical paper in the 15 May 1953 issue of Science,[8] which transformed the concept of scientific ideas concerning the origin of life into a respectable empirical inquiry.

Urey and Miller designed to simulate the ocean-atmospheric condition of the primitive Earth by using a continuous stream of steam into a mixture of methane (CH4), ammonia (NH3), and hydrogen (H2).

After a week of reaction, Miller detected the formation of amino acids, such as glycine, α- and β-alanine, using paper chromatography.

After waiting several weeks, Urey inquired and wrote to the chairman of the editorial board on 27 February on the lack of action in reviewing the manuscript.

As the knowledge of the Earth's early atmosphere progressed, and techniques for chemical analyses improved, he continued to refine the details and methods.

[14][15][16][17] With the recent revelation that, unlike the original Miller's experimental hypothesis of a strongly reducing condition, the primitive atmosphere could have been quite neutral, containing other gases in different proportions.

[19] In 1972 Miller and his collaborators repeated the 1953 experiment, but with newly developed automatic chemical analysers, such as ion-exchange chromatography and gas chromatography-mass spectrometry.

A note indicated that some were from his original 1952-1954 experiments, produced by using three different apparatuses, and one from 1958, which included hydrogen sulphide (H2S) in the gaseous mixture for the first time, a result which was never published.

Their result showed the synthesis of 22 amino acids and 5 amines, revealing that the original Miller experiment produced many more compounds than actually reported in 1953.

He was living in a nursing home in National City, south of San Diego, and died on 20 May 2007 at the nearby Paradise Hospital.

[10] Miller is remembered for his work concerning the origin of life (and he was considered a pioneer of the topics of exobiology), the natural occurrence of clathrate hydrates, and general mechanisms of action of anaesthesia.

[26] The Stanley L. Miller Award for scientists younger than the age of 37 was instituted by the International Society for the Study of the Origin of Life in 2008.