The way people watch television has changed dramatically since the medium first burst onto the scene in the 1940s and ‘50s and forever transformed American life. Decade after decade, TV technology has steadily advanced: Color arrived in the 1960s, followed by cable in the ‘70s, VCRs in the ‘80s and high-definition in the late ‘90s. In the 21st century, viewers are just as likely to watch shows on cell phones, laptops and tablets as on a TV set. Amazingly, however, all these technological changes were essentially just improvements on a basic system that has worked since the late 1930s—with roots reaching even further back than that.

No single inventor deserves credit for the television. The idea was floating around long before the technology existed to make it happen, and many scientists and engineers made contributions that built on each other to eventually produce what we know as TV today.

Television’s origins can be traced to the 1830s and ‘40s, when Samuel F.B. Morse developed the telegraph, the system of sending messages (translated into beeping sounds) along wires. Another important step forward came in 1876 in the form of Alexander Graham Bell’s telephone, which allowed the human voice to travel through wires over long distances.

Both Bell and Thomas Edison speculated about the possibility of telephone-like devices that could transmit images as well as sounds. But it was a German researcher who took the next important step toward developing the technology that made television possible. In 1884, Paul Nipkow came up with a system of sending images through wires via spinning discs. He called it the electric telescope, but it was essentially an early form of mechanical television.

In the early 1900s, both Russian physicist Boris Rosing and Scottish engineer Alan Archibald Campbell-Swinton worked independently to improve on Nipkow’s system by replacing the spinning discs with cathode ray tubes, a technology developed earlier by German physicist Karl Braun. Swinton’s system, which placed cathode ray tubes inside the camera that sent a picture, as well as inside the receiver, was essentially the earliest all-electronic television system.

Russian-born engineer Vladimir Zworykin had worked as Rosing’s assistant before both of them emigrated following the Russian Revolution. In 1923, Zworykin was employed at the Pittsburgh-based manufacturing company Westinghouse when he applied for his first television patent, for the “Iconoscope,” which used cathode ray tubes to transmit images.

Meanwhile, Scottish engineer John Baird gave the world's first demonstration of true television before 50 scientists in central London in 1927. With his new invention, Baird formed the Baird Television Development Company, and in 1928 it achieved the first transatlantic television transmission between London and New York and the first transmission to a ship in the mid-Atlantic. Baird is also credited with giving the first demonstration of both color and stereoscopic television.

In 1929, Zworykin demonstrated his all-electronic television system at a convention of radio engineers. In the audience was David Sarnoff, an executive at Radio Corporation of America (RCA), the nation’s biggest communications company at the time. Born into a poor Jewish family in Minsk, Russia, Sarnoff had come to New York City as a child and began his career as a telegraph operator. He was actually on duty on the night of the Titanic disaster; although he likely didn’t—as he later claimed—coordinate distress messages sent to nearby ships, he did help disseminate the names of the survivors.

Sarnoff was among the earliest to see that television, like radio, had enormous potential as a medium for entertainment as well as communication. Named president of RCA in 1930, he hired Zworykin to develop and improve television technology for the company. Meanwhile, an American inventor named Philo Farnsworth had been working on his own television system. Farnsworth, who grew up on a farm in Utah, reportedly came up with his big idea—a vacuum tube that could dissect images into lines, transmit those lines and turn them back into images—while still a teenager in chemistry class.

In 1927, at the age of 21, Farnsworth completed the prototype of the first working fully electronic TV system, based on this “image dissector.” He soon found himself embroiled in a long legal battle with RCA, which claimed Zworykin’s 1923 patent took priority over Farnsworth’s inventions. The U.S. Patent Office ruled in favor of Farnsworth in 1934 (helped in part by an old high school teacher, who had kept a key drawing by the young inventor), and Sarnoff was eventually forced to pay Farnsworth $1 million in licensing fees. Though viewed by many historians as the true father of television, Farnsworth never earned much more from his invention and was dogged by patent appeal lawsuits from RCA. He later moved on to other fields of research and died in debt in 1971.

Although the BBC had begun the world’s first regular TV broadcasts in 1936, Sarnoff used his company's marketing might to introduce the American public to television in a big way at the World’s Fair in New York City in 1939. Under the umbrella of RCA’s broadcasting division, the National Broadcasting Company (NBC), Sarnoff broadcast the fair’s opening ceremonies, including a speech by President Franklin D. Roosevelt.

By 1940, there were only a few hundred televisions in use in the United States. With radio still dominating the airwaves—more than 80 percent of American homes owned one at the time—TV use grew slowly over the course of the decade, and by the mid-1940s, the United States had 23 television stations (and counting). By 1949, a year after the debut of the hit variety show Texaco Star Theater, hosted by comedian Milton Berle, the nation boasted 1 million TV sets in use.

By the 1950s, television had truly entered the mainstream, with more than half of all American homes owning TV sets by 1955. As the number of consumers expanded, new stations were created and more programs broadcast, and by the end of that decade TV had replaced radio as the main source of home entertainment in the United States. During the 1960 presidential election, the young, handsome John F. Kennedy had a noticeable advantage over his less telegenic opponent, Richard M. Nixon in televised debates, and his victory that fall would bring home for many Americans the transformative impact of the medium.