Robert A. Moog, the creator of the most influential electronic music instrument in history, has died at the age of 71. Moog had been diagnosed with an inoperable brain tumor (glioblastoma multiforme) in April of 2005 and had been undergoing treatment. He died Sunday at his home in Asheville, NC. 

Moog ignited the world of electronic music by creating the modular electronic music synthesizer. Other electronic musical instruments came before, but Moog's was the first to achieve popular adoption by musicians. Besides engineering some of the most highly regarded electronic musical instruments of all time, Moog wrote extensively about electronic music.

In addition to his modular synthesizer, Moog is known for the Minimoog, a hugely popular portable synthesizer; theremins; and more recently, the Moogerfooger guitar pedals.

Moog's instruments were featured prominently in work by Walter Carlos, Isao Tomita, Emerson Lake and Palmer, Tangerine Dream, Klaus Schulze, The Beatles, Yes, Devo, Stereolab, Stevie Wonder, hundreds of "switched-on" records, Giorgio Moroder, and electronica artists everywhere.

Moog was born May 23, 1934, and grew up in New York City. As a young man, he was fascinated by the theremin, the earliest electronic instrument to garner popular interest. He wrote an article on building theremins for Electronics World magazine, and went into business selling theremin kits to go along with the article. He studied physics and electrical engineering in college, and earned a Ph.D. in engineering physics from Cornell.

Moog drew heavily on the input of musicians in creating his electronic instruments. He worked with academic and popular musicians alike, and by making his instruments usable by gigging musicians, he also made them reliable studio tools.

The Moog Modular Synthesizer, 1963-1964,  revolutionized the electronic music studio. It featured voltage-controlled modules that were more flexible and reliable than previous tools, because they were systematically designed for creating electronic music. In addition to voltage-control, Moog's synthesizer featured Attack-Decay-Sustain-Release envelope generators, which became a standard feature of analog synths.

The Modular also introduced the Moog ladder filter, the source of much of Moog's unique sound. The importance of Moog's voltage controlled filter to electronic music would be hard to overestimate. Widely regarded as one of the most musical filter designs ever created, it let users create a wide range of sounds that helped define the analog synth.

The first Moog record is thought to be Cosmic Sounds by The Zodiac. The record was "head" music by Mort Garson, a composer of many exotica records.

The Moog synthesizer was rapidly adopted, and the success of Walter (Wendy) Carlos' Switched-On Bach led to an explosion of Moog-themed recordings.

Moog called 1969 "The Year of the Moog", because "Moog fever" hit an all-time high that year. Moog's name became synonymous with the exotic, futuristic, otherworldly and sexy sounds of popular electronic music.

While Moog's Modular Synthesizer defined the synthesizer, it was the Minimoog that made the synthesizer a widely used instrument. The Mini was a portable version of the modular synths, with internal patchings and switches that made it easy to quickly switch between sounds. It was widely popular, being used on thousands of albums. The Mini is more popular than ever today, with vintage Mini's selling for thousands of dollars. Moog recently introduced an updated version, the Minimoog Voyager.

Moog's family announced his death. "On Aug 21, 2005 Bob Moog passed away. He was a gentle and humble man with a wonderful sense of humor and a brilliance that inspired millions around the world. Your posts in the guest book have warmed our hearts."

Moog is survived by his wife, Ileana, his five children, Laura Moog Lanier, Matthew Moog, Michelle Moog-Koussa, Renee Moog, and Miranda Richmond; and the mother of his children, Shirleigh Moog.