Short answers, pulled from the story.
The Moog synthesizer was designed by the American engineer Robert Moog and first sold in 1964. It was built from separate modules connected by patch cables, and Moog developed the voltage-controlled oscillator to control pitch through voltage.
The Prophet-5, released by the American company Sequential Circuits in 1978, was the first fully programmable polyphonic synthesizer. It used microprocessors to store sounds in patch memory, allowing users to save and recall sounds for the first time.
Released in 1983, the Yamaha DX7 was the first commercially successful digital synthesizer and the first synthesizer to sell more than 100,000 units. It used frequency modulation synthesis developed by Stanford engineer John Chowning and became a staple of 1980s pop music.
The Korg M1 is the bestselling synthesizer in history, with more than 250,000 units sold. Released in 1988, it was a digital synthesizer workstation featuring sampled transients and loops, and its presets were widely used in 1990s house music.
Switched-On Bach, a bestselling 1968 album of Bach compositions arranged for Moog synthesizer by Wendy Carlos, showed that synthesizers could be more than random noise machines. It took the synthesizer into the mainstream after it had been seen as an avant-garde instrument with little commercial potential.
Synthesizers threatened session musicians because one keyboardist or programmer could imitate strings, horns, and the range of an entire orchestra. The American Federation of Musicians banned the Moog from union work for a period, and in 1982 the British Musicians' Union tried to ban synthesizers after a Barry Manilow tour used them instead of an orchestra.