Charming! So charming! It's pretty much the love child of ye olde historicale romance and ye alsoe olden mystery, but it's all done with a really pleasing awareness of women's place and restrictions in European society in the 18somethingorothers, without losing its effervescence. It's half romance novel-ish social machinations, half political intrigue, and it totally passes the Bechdel test while still verging on traditional romance novel territory with a cracking mystery. I enjoyed the heroine's post-mortem infatuation with her recently-deceased husband, which pokes at the trope of the universal romance novel young widow, while also giving the heroine interesting ways in which to grow. Also, I totally dig the Society lady's transformation into full-on Greek geek.
There's some weird colonial stuff (her husband's a big game hunter in Africa, which is treated pretty much as a monolithic whole, plus antiquities - AWKward), but it's fairly self-conscious weirdness, in which I think (hope?) the author is being "historically accurate" and we're meant to find it weird. Again, I hope. Other than that, thoroughly charming read.