This was a very hard book to read - actually, it's dense. The fact that it's contain a lot of poetry also made it a little more difficult for my progress in the reading, for I don't always grasp all the meaning in the poetry, and this is very important to understand the story being told. But despite the hard work to read it the book is indeed beautiful, even being sometimes so sad. And it's strange for me to think that in a book so full of feminist narrative, the author made me love most the two main male characters. It's probably one of fact that demonstrate how A.S. Byatt is genial in her prose, with all the use of poetry, to describe a romance.
One excellent review: http://www.guardian.co.uk/books/2009/jun/20/possession-as-byatt-book-club