When you submit a paper / manuscript to a peer-reviewed venue, the organizers usually forward your work to 2-3 other "experts in your field" to assess your work.
I'm curious how this process of selection works, i.e. how is this pool of reviewers put together? and how are the best people from this pool chosen once there is a paper to review?
Is there an official list that each venue maintains and to which people can sign on if they want to be reviewers? (If so, I've never seen any "calls for reviewers" so how do they get people?)
Do organizers cold-call people/professors and ask them if they were willing to review a paper? If so, how are these people selected? [I realize that this might differ considerably, so I'm happy with anecdotal evidence, too]