I studied Book 9 for A Level and then the whole at degree level. I agree with everything Michael Steen says. This is brilliant, thought provoking, passionate and sometimes heartbreaking poetry. Satan is definitely the most compelling character, but I do love Raphael too, especially in Book 4 when he comes to warn Adam and Eve. (In fact I love it so much have quoted it in my latest book). PL should be required reading. It may feel like a bit of a struggle to get through, but definitely worth it.