Bennett Glotzer (1933? 1934?- 29 July 2020) was Zappa's manager from 1976 to 1981.
He was originally manager for Janis Joplin, The Band, Lightfoot, Seatrain, Tom Rush, Paul Butterfield, Blood, Sweat & Tears and Procol Harum. Glotzer was additionally associate producer for Zappa's films Baby Snakes (1979) and Dub Room Special (1984).
In the early 1990s he started the educational video project The Education Group.
He passed away on 29 July 2020 at age 86. 
IT: Who is your new manager?
Zappa: It's a problem for the manager.
Frank Zappa: Well, I've got a videotape that was made in the promoter's room in Pistoia, Italy, when he had refused to pay some parts of the crew, and he was in danger of not paying the band for going on, and the manager that I had at the time, Bennett Glotzer, had just punched this guy out. [laughter] He was about a foot and a half taller than him, and he just hit him in the face about fifteen times. I heard about this, and I told Nordegg, Thomas Nordegg, who was operating the video camera, "Thomas, go and take pictures of this." And so, he dutifully went in there, and nobody believed that the camera was rolling. He got coverage of this meeting with these guys, I mean, they have this table full of lira, and there's all these mafia-looking guys, and they're shoveling this stuff around, and this promoter is explaining in these very lame terms why he hadn't paid, and [laughter] Bennett, y'know, like, screaming at him, and Thomas just walking around there very calmly video-taping the whole thing. I got that. Then a few years later, this promotor, Francesco Sanavio [?] [c], came to Los Angeles, and he had the nerve to call up and say "Can I come over?", and I said "Sure. Come on over", and I made him watch the tape, and he said "I didn't believe that there was any tape in the camera." Here he is looking at himself doing all this stuff. He's in jail now. [laughter] In Italy.
Eric Buxton: Never believe there's no film in the camera. Never.
Frank Zappa: That's right. Not with Nordegg, that's for sure. [laughter]
- Quoted from They're Doing the Interview of the Century, Part 2.