HBP: Chapter 9 - The Half Blood Prince

I found it quite convient that Slughorn took over potions this year so Harry and Ron could continue with the course. Were Harry and Ron the only ones who benefited from Slughorn taking Snape's old teaching position? They were the only ones who seemed to need textbooks and supplies...

So Snape finally got his wish to teach DADA and this is the only lesson we get to see? How dissappointing. But we do learn about nonverbal spells so they must be important. So can all spells be done nonverbally? How many wizards can do nonverbal spells? How often are they used? Have we encountered or been affected by a nonverbal spell without realizing it? That's kinda scary...

I'm curious what grades everyone got on their O.W.L.S and what classes they are taking now. I'm nosy what can I say. Besides the trio we really aren't told. It appears that Draco did quite well. He seems to be in all the same classes as the trio. For some reason I want to think that if it wasn't for Hermione he would have had the best marks in the class. Second best again? Seems appropriate.

So Slughorn is it really safe to have all these potentially dangerous potions all mixed and sitting around? Anyone steal and use any of these potions? We assume that Malfoy stole some of the Polyjuice potion but if that's the case why didn't he steal some of the Felix Felicis that he so desperately wanted to win? Did he make his own then? Were Crabbe and Goyle the only people at Hogwarts under the influence of Polyjuice potion? It is mentioned several times to watch out for imposters using Polyjuice potion. Is there someone out there who isn't who they appear to be?

There are several references back to PS and CoS. In PS Snape introduced us to the Draught of Living Death and now we are making it in class. Also in CoS we learned to be afraid of old books (which Ginny so kindly reminds us of). Are these references just nice continuances that JK to connect the different books or are they hints that we should go back and reread cause they hold clues to how the story will end?

Now knowing that Snape is the half-blood prince I have several questions. When did Snape write in this potions book? Was he a student at Hogwarts at the time or was it during his time as a professor? Seems quite advanced for the average student. If it was during when he was a student we know (and have been reminded repeatedly) that Lily was also very talented at potions would she have known about the textbook or are there any references to her in the book? Harry says that the book was from 50 years ago that made him think that it couldn't have been from his parents time at the school. Did someone else have the book before Snape (like Lucius Malfoy)? Was he the only one to write in it? Seeing how much effort Snape put into writing notes in this book it seems odd that he didn't keep better track of it and left it lying around so a student could use it. Was it meant to get to Harry or was that an accident? Is the book hiding any more secrets that we are unaware of? So many possibilities... So much to think about...