Let's review this in cliches.
I fell for this book the way Hazel fell for Augustus: slowly, and then all at once.
It was a privilege to have my heart broken by it.
Alright, now that's out of the way. Let me just say that this is, without a doubt, one of the most emotional experiences I've ever had reading a book. As much as I have thoroughly enjoyed all of John Green's books and eagerly look forward to his next, this is his magnum opus, the book everyone will remember him for. Beautiful literature that, like all great literature, transcends age range labels. Young Adult literature-haters (rare though I hope you are) don't put this one off.