One of the things I was most glad to see in The Half-Blood Prince, is that at least my thoughts on patronage networks seems to have been borne out - even if a number of my other speculations have proved rather further from the mark! Slughorn’s club (and it’s after-school connections) was beautiful in this regard - and especially the way that Riddle learned from it!
Now, about Snape and Lily.
We know from what Remus Lupin said in Order of the Phoenix that Lily did not become especially close to James until his last year, though it seems that he had always liked her. But it’s only in reading this last book that I’ve started to believe that until this, she really could have been quite close friends with Snape.
They would definitely have mixed socially. They were both members of Slughorn’s club, and (with what Horace said about Lily, and Snape’s potions genius) they were his favourites in their year. “And” he had a consistent practice of setting up connections between his various protégés. I am quite confident (given that Gryffindors and Slytherins take Potions together, and all houses do, in the last two years) that Slughorn paired Lily and Snape together for potions, consistently - perhaps for years.
Which could explain why, although the book was defined as Snape’s by the name of the “Half Plood Prince”, and many spells in it are “known” to be Snape’s own inventions, and Harry was convinced that it belonged to a boy, Hermione was also convinced that the handwriting in it was a woman’s. If Harry had shown the book to Remus Lupin, would he have recognised the handwriting as Lily’s? If they had worked together in Potions, using the same textbook together, and adding in their additional refinements, I think this is entirely plausible. And actually, the strange sense of humour that Harry observed may owe something to Lily too - the sort of Lily that liked playing practical jokes on Petunia. I can imagine the wry humour with which, when Snape referred to the book as his own, she wrote (in place of his real name) she wrote inside, that it belonged to his "preferred" name, of the Half Blood Prince.
Perhaps "half blood prince" is not a mark of ownership, but a "dedication?"
Could this also explain how James got hold of Snape’s spells. Was it through Lily? Or did Snape think that it must be through Lily? (Probably James watched him practice, through his invisibility cloak). Does this account for some of Snape’s reaction to her in the pensieve scene? A mistaken sense of betrayal of secrets?
Oh well! Just an idea!
More detailed post to follow, about the rest of the book!
----