This was my final published TJR backlist read! I do have an IG post sort of about this book but really more about the challenge it wrapped up for me, so this is the official review. It is a short story or novella vs a full novel, written all in the epistolary style. The letters are writtten betwen a woman who finds clandestine letters between her husband and the wife of the man she writes to. She writes to tell him about the affair and they keep in touch while trying to gather more evidence about their spouses's infidelities, and end up growing closer themselves. It has a bit of a twist or surprise at the end which, from comments I've seen in various places, people are very hit and miss about--I wasnt too surprised by it, so I was not shocked or bothered.