Yeah, um, no. This is not going to be a favourite.
The psychology of the MC, i.e. Dame Agatha, is all over the place ... not at all what she comes across as in her autobiography.
With all due respect, but this book is probably more enjoyable if one doesn't know anything about her or her books at all, because if one does many of the "revelations" are rather obvious and "old news". Some of the "facts" also seem different from what I remember, but I have not looked into the details of this, yet.
And I was not keen on Wilson describing a character in a Christie mystery as a villain, which was as good as giving away the twist...gah, why do people do this?
The writing is not bad, tho.