There are passages in which Byatt's descriptions are breathtakingly eloquent. More often than usual when I read, I find myself setting the book aside to reflect more deeply and slowly on the richness of the content. She renders the subtleties of her characters' interior lives with such precision that one feels they are real people in real situations, rather than mere fictions of her mind.
The poems within the book deserve a separate comment and far more praise than I can give them here. I am astonished that Byatt has written these poems herself, attributing them to her poet-characters Randolph Henry Ash and Christable LaMotte. They would stand up well against any highly-regarded poetry of the era. I thoroughly enjoyed them, although my taste in poetry generally leans away from the overwrought High Romanticism of the Victorian poets... not all of them, of course. Some of my favorite poets are among this group. However, in my opinion, this type of poetry must be executed flawlessly or avoided completely. There is no middle ground, as there is nothing worse than reading the fumbled efforts of the Romantics, which come across as sentimental gushing and the vomiting of too many poorly chosen words. It's like a potentially delicious meal prepared by a bad cook, inducing nausea in all who partake.
For myself, I am pleased to say that I feel I have finally grown into Byatt's writing. I believe I am now a more worthy reader of her books than I was when I was younger. If I love "Possession" more profoundly now than I did then (and recently found "The Children's Book" to be a miracle in itself), it is only because I have changed, not the books. I needed to experience more, know more, and become more before I could fully grasp the depth and breadth of Byatt's intellectual, artistic, and emotional brilliance.
She writes densely, so her books will not be enjoyed by those who prefer minimalism or terseness or are in a Hemingwayesque mood. However, not for the first time in my life, I have been longing for labyrinthine books lately. I am very much in the C.S. Lewis state of mind that led him to say, "You can never get a cup of tea large enough or a book long enough to suit me." Hear, hear! But it's even better when the book is magnificent and the tea (or coffee) is perfectly brewed. I am glad that now I can go back and read all of Byatt's books that I've overlooked, and also that she is still alive and writing, so there will undoubtedly be more to look forward to!

The Mermaid, Edward Burne-Jones, 1882 (The Tate, London).