I took out Possession twice from the library. I couldn't finish it the first time... it was so DENSE. (A very common reaction, I've since learned, when reading Possession.) But after you get over a particular section involving very long-winded letters between two Victorian poets, the story goes reeling and I ended up in tears near the end... I can still quote from the letter Christabel LaMotte wrote to Ash, a letter that never reached him.
Hell. Who DOESN'T want to have loved somebody that much?
I don't think many critics have mentioned this, but to me, the supporting characters really MAKE the book. I was touched by Byatt's knowing yet sympathetic portrayal of Ellen Ash, who very secretly wished to be a poet but became the lantern bearer for one instead, or of Dr. Beatrice Nest, a mild literary scholar working on "womanly work" when she really wants to sink her teeth into what truly makes her tick, the painter Blanche Glover and her descriptions of light and the depiction of force (the complete text of her suicide note is given at one point)... there's a very, very moving passage around the end of the book where Ellen sifts through the remains of Ash's things and decides what to do with Christabel's letter.
For the aspiring writers out there, there's an important passage on words around the end where Roland suddenly discover's he's a poet and the poems "fall like rain." I know everyone hates the poems but they are really worth reading and thinking about; if you like Emily Dickinson you'll love Christabel's poems. I hope Byatt has the full text of "Ask and Embla" somewhere.
The best thing about Possession is that it understands people who think literature MEANS something beyond being a lovely way to kill time. It understands those quiet but passionate people you see browsing in bookstores, who write reviews on Amazon.com, who, at a used bookstore, find joy in finding an out-of-print-book they've been DYING to read for years. It's a book that understands YOU.