Keyboards and synthesizers are instruments that electronically replicate the sounds of pianos, organs, strings, horns, woodwinds, and even voices. One of the first synthesizers was the Novachord, which had 169 vacuum tubes, weighed in excess of 500 pounds, and made its debut at the 1939 World’s Fair in New York, where a quartet of Novachords, plus a Hammond organ (Laurens Hammond was one of the machine’s designers), serenaded visitors to the Ford Motor Company Pavilion with other-worldly sounds.
Another mid-20th-century keyboard pioneer was Robert Moog, although he cut his teeth on making kits for keyboard-less Theremins in the 1950s. By 1964, though, Moog had created his first synthesizer, which featured two keyboards and a pair of freestanding modules, each riddled with jacks and knobs.
In fact, the 1960s were a formative decade for electronic keyboards. The Mellotron Mark II appeared in England in 1964, and was immediately embraced by Mike Pinder of The Moody Blues, who used the instrument on songs like “Nights in White Satin.” Pinder was an effective evangelist for the Mellotron in England, convincing The Beatles to use it (you can hear its "flute" intro to “Strawberry Fields Forever”), and that got it on the radar of prog-rockers like Genesis and Yes. Around the same time, Hohner, whose claim to fame had been harmonicas, introduced the Clavinet. Simpler by several orders of magnitude than a Moog or even a Mellotron, the Clavinet was supposed to be an electronic Clavichord, but it sounded nothing at all like a staid Renaissance instrument in the hands of an artist like Stevie Wonder, whose funky 1972 hit, “Superstition,” was performed on a Clavinet C.
In the 1970s, electronic keyboards were suddenly everywhere. EMS in London introduced a string of products throughout the decade (Pink Floyd was a big customer); ARP of Lexington, Massachusetts, produced formidable competitors to the Minimoog (its Odyssey and 2600 models were big sellers); and in 1977 a company called Sequential Circuits introduced the Prophet-5, which was the first machine that could store a musician’s customized sounds, known as patches. In the 1980s, though, digital synthesizers and keyboards, many from Japanese manufacturers such as Yamaha, Roland, and Korg, elbowed analog devices out of the marketplace, although vintage analog keyboards and synthesizers are still sought by discerning musicians.