For now--4. [UPDATED to 5. I actually on a whim started rereading, and before I knew it was on about 50, and, yeah, it's amazing.)] This was amazing, and I kind of parcelled it out as a reward in small chunks each night, after drowning in the grading of papers.... It may climb to 5, but give me a few days to think about my reaction.
I will say, in brief: it is a great story, compulsively engaging the reader in terms of plot, untangling its interwoven narrators' stories. And each has a voice--particularly Florens--that sees that shared world fresh, distinctively. And it's one of those rare "important" novels that illuminates by enthralling you, rather than elucidating major ideas (or banging you over the head).