The Sonnet Lover by Carol Goodman
As I mentioned in this post, I've read and enjoyed quite a few of Goodman's books. At this point, the only one I haven't read is her most recent: Arcadia Falls.
I was excited about reading The Sonnet Lover because I tend to find Goodman's novels compelling and atmospheric. I thought Shakespeare would be an interesting addition to her literary thrillers. By the way, I must point out that the novel's synopsis (which you can see in this post) is a bit misleading: the previously-unknown poems that are discovered were not written by Shakespeare, but supposedly by his "dark lady."
Unfortunately for me I'd read The Night Villa (see post) fairly recently. The Sonnet Lover was published before The Night Villa (in 2007 and 2008 respectively), but they their plots are very similar: different location, different rare literary documents, but more or less the same plot. I knew fairly early in the story, who the bad guy was. The person in question was one of a few candidates for that role, but because his/her counterpart in The Night Villa ended up being the villain, I paid closer attention to his/her words and actions than I might have if I hadn't been familiar with The Night Villa.
While disappointed with The Sonnet Lover I'm still open to reading more of Goodman's work in the future. I'll just need to be sure that I allow myself larger gaps between readings of her work.