Thanks for the recommendation!
"Spellbinding" is a cliche but I don't think it is too strong in this case. I finished the book last night and was still distracted this morning thinking it over. As much as I enjoyed it I can't help but feel a little bit tricked in way, I'm not sure how much any of the deeper meanings/insights that appear to be promised really pan out. But, then I'm not sure how much it matters when the ride itself is amazing. And there are so many wonderful parallels between the experience of the protagonist and the experience of the reader. The reader, after all always submits to the machinations of the author - and even when you think you have broken the author's "rules", how do you know that itself was not part of the authors intention?
There are some wonderful small details too. Like Conchis telling Nicholas early on not to wonder how, but why. And in one of Lily's and Nicholas's last meetings she pleads with him to remember not only why, but how. And Conchis telling Nicholas he burned all of his novels because it was not worth all of those words for one bit of truth at the end, which is deliciously ironic in reference to this novel in particular.
The most similar book I've read is probably "The Name of the Rose" by Umberto Eco, which is bit lighter but incredibly fun if you can make it through the first hundred pages or so. I suppose they are both considered postmodern novels. I look forward to reading more Fowles.