Let's pretend that I am on your Comprehensive Exam committee for a PhD in Blues. In classical music, I might ask the student to talk about opera in the United States. I didn't like to focus the questions too much, preferring to see how the student presents the topic. It usually takes around 5 minutes to hit the main points. OK, so here is my question for your imaginary comprehensive exam. It wouldn't be sporting to let you use Google, as this is an off-the-cuff, oral exam question. The students won't know what I'm asking, but part of their education and training is to have a broad enough knowledge of their entire field. OK, here is your question. "What is the history of the minor blues?"