Another book I never really knew the plot to but always heard referenced - and whose movie I'd never seen. What a delight! This is exactly the kind of plot I enjoy. Very mid sci-fi, a bit of spookiness, and overall well written. Levin writes in a way that immersed me into the story, felt like I was there, without being overly descriptive or wordy. 

I don't always love an open ending, but I think this one was just right. Poor Joanna.