Their are 4 main areas of the music industry. The first area I am going to write about is live performance. The live performance part isn't just the people on the stage or the entertainers, their are a lot of area's to live performance.

Firstly, I am going to write about the people who set up the performance.

Most artists have agents, these are the people who book the event for the person they work for. They search around looking for (e.g. arenas), and try to book their artist in.
Also, artists have promoters. These are the people who try and get their artist known, whether it be by posters, billboards, social network, magazines etc. These are the people who hunt around and take every opportunity to advertise their artist.
Another part of the live performance is the venue managers. These are a huge part of the live performance in the music industry, because these are the people who agree to let the artists perform in their venue. If the venue managers didn't agree to let the artist perform, then the agents wouldn't have a job to do and the artist wouldn't get more known.
The final part of the live performance is the artists. These are the most important part, as these are the entertainers. The artists could be drummers, guitarists, bassist, vocalists, dancers, any other musician or even a comedian. These are the people who perform for everyone else's entertainment, however they need people to work for them so their work doesn't get overwhelming, and they must pay a certain percentage of the money that they earn to the people who work for them.
The artists manager is the person who manages the staff who work for the artist, or manage the dates of when the artist is booked in to perform. The manager could also help promote the artist.
Another sector of live performance is a runner, these are the people who tend to the artists needs - maybe by carrying their instruments or equipment, driving, or little things like getting the artist food or drink when...