On the occasion of Robert A. Moog's birthday, here's an excellent interview from The Guardian. The original interview was by Don Snowden, published in the Los Angeles Times in 1981.
“Emerson, Lake & Palmer performed at Gaelic Park in New York City and it was incredible,” Moog recalled. “There were 10,000 kids standing on a soccer field and here's Keith Emerson sticking knives in a Leslie cabinet. A New York musician who had bought some of my equipment was there and he was in complete shock. He said, ‘This is the end of the world.’”
Emerson's wild-man-of-the-opera stage antics may have shocked some of Moog's more conventional customers but they thrilled many rock fans. ELP quickly became one of rock's most successful attractions and paved the way for other progressive rock bands like Yes and Genesis.