1920 to 1950

The word robot was popularized by Czech author Karel Čapek in his 1921 play R.U.R. (Rossum's Universal Robots). According to Karel, his brother Josef was the actual inventor of the word "robot", creating the word from the Czech word "robota", meaning servitude. In 1927, Fritz Lang's Metropolis was released; the Maschinenmensch ("machine-human"), a gynoid humanoid robot, also called "Parody", "Futura", "Robotrix", or the "Maria impersonator" (played by German actress Brigitte Helm), was the first robot ever to be   depicted on film. The world's first actual robot, a humanoid named Televox operated through the telephone system, was constructed in the United States in 1927. In 1928, Makoto Nishimura produced Japan's first robot, Gakutensoku.

In his 1936 paper "On Computable Numbers, with an Application to the Entscheidungsproblem" (submitted on 28 May 1936), Turing reformulated Kurt Gödel's 1931 results on the limits of proof and computation, replacing Gödel's universal arithmetic-based formal language with what are now called Turing machines, formal and simple devices. He proved that some such machine would be capable of performing any conceivable mathematical computation if it were representable as an algorithm, thus creating the basis for what is now called computer science.

Many robots were constructed before the dawn of computer-controlled servomechanisms, for the public relations purposes of major firms. Electro appeared in Westinghouse's pavilion at the 1939 New York World's Fair. Some were built in between such major public gatherings, such as Garco, made by Garrett AiResearch in the 1950s. These were essentially machines that could perform a few stunts, like the automatons of the 18th century.

Vannevar Bush created the first differential analyzer at the Massachusetts Institute Of Technology (MIT). Known as the Differential Analyzer, the computer could solve differential equations. 1940 brought about the creation of two electrical computers, John Vincent Atanasoff and Clifford Berry's Atanasoff-Berry Computer (ABC).

Concepts of the ABC were later used in the functional ENIAC.

In 1941 and 1942, Isaac Asimov formulated the Three Laws of Robotics, and in the process of doing so, coined the word "robotics".

In the UK, the Robinson machine was designed for the British war effort in cracking Enigma messages. This was done at the British code-breaking establishment at Bletchley Park; Ultra is the name for the intelligence so received.

Robinson was superseded by Colossus, which was built in 1943 to decode FISH messages by the British group Ultra; it was designed by Tommy Flowers and was 100 to 1000 times faster than Robinson, and was the first fully electronic computer. The Bletchley machines were kept secret for decades, and so do not appear in histories of computing written until recently. After the war, Tommy Flowers joined the team that built the early Manchester computers.

In Germany, Konrad Zuse built the first fully programmable digital computer in the world (the Z3) in 1941; it would later be destroyed in 1944. Zuse was also known for building the first binary computer from 1936 to 1938,  called the Z1; he also built the Z4, his only machine to survive World War II.

The first American programmable computer was completed in 1944 by Howard Aiken and Grace Hopper. The Mark I (as it was called) ran computations for the US Navy until 1959. ENIAC was built in 1946 and gained fame because of its reliability, speed, and versatility. John Presper Eckert and John W. Mauchly spent 3 years building ENIAC, which weighed over 60,000 lbs.

In 1948, Norbert Wiener formulated the principles of cybernetics, the basis of practical robotics.

The first Turtles (Elmo and Elsie) were created by pioneer roboticist William Grey Walter in 1949.

The first working digital computer to be sold was Zuse's Z4 in Germany; the fully electronic US BINAC was sold twelve months earlier in September 1949 but it never worked reliably at the customer's site due to mishandling in transit. Second was the UK's Ferranti Mark 1 delivered in February 1951, the first software programmable digital electronic computer to be sold that worked upon delivery. It was based on the world's first software programmable digital electronic computer, Manchester's SSME of 1948.

In 1950, UNIVAC I (also by Eckert and Mauchley) handled the US Census results; it was the third commercially marketed computer that worked on delivery (in December 1951).

The Turing test is proposed by Alan Turing in his 1950 paper Computing Machinery and Intelligence, which opens with the words: "I propose to consider the question, 'Can machines think?'"