What is a control block?

Question

Processors

We have a generalized process switch consisting of -
1. Save the state of the process, (registers)
2. Update the control block
3. Transfer the control block to the appropriate queue - ready, blocked ...
4. Select the next process
5. Update the control block of the new process .
.........
Question - a control block is obtained and is a process in the general case. In the sense that when there is no work on the process, do I perceive the block control data as a process or how, if I operate on it?
And secondly: can you advise, normal material on operating rooms, except for Tenenbaun, otherwise not everything is clear, I would like more parallel information.