Agatha Christie books take me about 2-3 hours to read. I could read one every evening, but probably will just cover 3-4 each week. Time will tell.
I started reading Agatha Christie novels when I was 8. I do not say this to recommend that course of action or to promote the notion that I was a precocious reader. My interest in the books is informed largely by that fact, is the thing.
My mom collected them, in a funny old bookcase I would love to now own. It was low and wide, with two open shelves at the top, and louvred sliding doors at the bottom, standing on 3-4 inch legs. Kind of a medium oak, dull finish, very sturdy, very MCM. The James Bond books were inside it, and a few of those Reader's Digest Condensed books, and some other things. Knowing my mother, none of them had been purchased new.
I do have a bookcase, by the way, that I've had since childhood. Mom got it at a garage sale for me, painted it fresh in the backyard, and I've been using it ever since, though now and then it's been in a kid's bedroom. It's been half a dozen different colors. Right now it is just sort of beige. It's in the dining room and holds cookbooks.
So Mom was on a Christie jag one summer, and I was out of things to read. I'd already filled out several of those "read 20 books/choose a book to own" lists at the library. I never had enough to read. I asked her if I could read an Agatha Christie book, and she said she would have to approve my selection. So I chose Hallowe'en Party, because it had a girl in it, and people bobbing for apples.
I'm not sure she thought I'd finish it, but she agreed I could read it. I did manage to finish it, and another one, And Then There Were None, before moving on to other book interests, and didn't pick them up again for a couple of years. When I was about 10 or so, I started reading them again—I think it was because of that Agatha Christie movie mini-trend going on just about then (which I will touch on another time)—and Nero Wolfe stories as well, and have kept it up ever since. The order in which I read them had mainly to do with my age at the time, but also I just started with whatever was in our bookshelves at home, then moved on to the selection at the library.
When I first read Hallowe'en Party again as an adult, I had to wonder if my mom actually noticed or reflected on the lesbian subtext. It would be interesting to ask her. Also, what titles, if any, she'd have said no to back when I first wanted to read them.
In 1991, shortly after I was married, I told the eventual LP that I'd like to collect Agatha Christie books, because I mourned the loss of Mom's collection. He let me parse out a bit of grocery money at a time for them, and over the next few years I ended up with all of them. Now and then one goes away, and has to be replaced. But I still have most of my original copies.
I couldn't find this exact cover on the web, so I scanned it and a few others today. It's pretty worn, as it's one that has been read by several members of the family. I'm not sure why it has paint on it. Most of my "nice" books are in very good or excellent condition, but these things are made to be carried around and loved, you know? So they get wear and tear.
The Secret Adversary is on my "definitely recommend" list, especially for anyone who enjoys reading about the World War One era and the years immediately following it. It is the first in a series of five books about Tommy and Tuppence. If you look them up, you will see that they take the form of four novels and one short story collection. But that's misleading; the short stories are in a simple plot framework and read like novel chapters as well as individual stories. So you can read the five books in order and watch how they progress.
Tommy and Tuppence are very young in their first story. I think Christie already realized that by making Poirot so old in the beginning, she'd limited him to a pretty narrow space. So Tommy and Tuppence get to grow up and grow older in their stories, and that informs their behavior and decisions. Also, their stories are more specifically related to the time period in which they were written.
The Secret Adversary is a bit slow, action-wise, through the first half. There's a lot of chatty dialogue, mostly light and engaging. It doesn't read as much like a detective novel as many of the other books; it's more like a very lightly romantic adventure. The other characters are pretty stereotypical, but I think Christie had a lot to do with defining those stereotypes, which is kind of fun to consider.
You don't—at least I don't—read these stories in order to figure out "whodunit" as quickly as possible. You read them the way you watch an old favorite movie while savoring a tub of quality ice cream. The experience is in watching it all play out, not in seeing how clever you can be in a competition against the author. I think many people will figure out whodunit it in this story well before they have finished. But it's still a fun and charming ride to the end, and there are a couple of neat little twists in the conclusion.