ERB isn't actually a part of Rails. Rails just uses it to parse ruby code within a text file (such as an HTML document). The only magic you really need to keep in mind concerning how the view relates to the controller is that it has access to the controller's instance variables. The view also has access to helper methods, but those don't have anything to do with the controller or model.
If you are more interested in the inner-workings of the view and the controller, I think the Agile Web Development with Rails book touches on this subject a little. IIRC, it shows you how to use something other than erb to parse the view file.
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