4.5 stars -- Wow. This was a slow burn that got better and better as it went, which I honestly find to be somewhat of a rarity in whodunnits. To level set, this is basically a set of interconnected short stories that has an interstitial framing narrative that pops in from time to time. The framing device seems to be set approximately in the mid-1960s, but all the short stories are set in 1930s & 40s England, and each short story plays with different sub-tropes of golden age whodunnits. At the beginning of the book, I was into it but thinking, OK this is pretty good, but nothing too exciting. By the time we got to the middle section of the stories where we had a locked room mystery followed by a really high quality isolated closed circle mystery, I was like, yeah, this is actually really good. But the way this book stuck the landing, at least for my tastes-- I thought it struck a great balance between some expected elements to the resolution but executed in a really exciting and fun way. All in all, I had a great time with this book and think it's a "mystery lovers' mystery."