Whew, @nxnwrocks , that is all of them! I don't think I could do that without some long and hard thought--and, moreover, I haven't read all of AC's spy thrillers--so, if you'll allow me instead to re-post some "top 10" thoughts that I've previously posted elsewhere...
10.
The A.B.C. Murders (1936): marvellous, one of her smartest jobs, with an excellent manhunt for a mad (or apparently mad) murderer. The identity of said murderer is breathtakingly brilliant, with incredible misdirection. If Hastings, in one of his last appearances, if more than a bit annoying in his thickheadedness, the Alexander Bonaparte Cust parts more than make up for it. The clues, let me say, are first-class. A classic.
9.
Murder on the Orient Express (1934): her most famous, probably due to the movie, which is fun but slow-moving for long stretches. The book, mercifully, is far better; the interviews actually increase the tension of being stuck on the snowbound train with a murderer who stabbed a loathsome American gangster in his locked cabin. The solution may be far-fetched, but (
Raymond Chandler notwithstanding) we are too busy marvelling at it to worry. And pure magic is evoked by one of the simplest lines in all Christiedom: “The Orient Express had started on its three-days’ journey across Europe.”
8.
Murder is Easy (1939): though little-known, this is a masterful tale of witchcraft in a small town, sort of St. Mary Mead turned on its head, with detection by ex-policeman Luke Fitzwilliam, Supt. Battle, and a number of amateurs. The characters are excellent and the detection delightful; the book becomes genuinely unnerving at the end, akin to Carr; and the identity of the murderer is one of Christie’s best surprises. Unfortunately, what keeps this book from the top 5 is the lack of clues; there is no single clue that will allow the reader to deduce the villain; but said reader may be having too much fun to complain.
7.
A Murder is Announced (1950): the only Marple on my list, but it’s probably the best of the Marples, with an excellent plot, a fast-moving story, and good characterization. The murderer announces his crime in the local paper, leading to an excellent why problem; indeed, the revelation of the motive may be even more ingenious than the revelation of the murderer. One of Christie’s best.
6.
Endless Night (1967): a shocker, to such an extent that the reader may actually be angry upon finishing the book. It is without a doubt the darkest and most sinister book she ever wrote, prefiguring, in fact, some of Ruth Rendell. The characterization is superb, and the plot (borrowing in part from her Marple short “The Case of the Caretaker”) pulls the rug out from under the reader’s feet and leaves him reeling. Brilliant. As Nick Fuller
realized, note similarities to
Death on the Nile.
5.
Five Little Pigs (1943): the first and best of the “murder-in-retrospect” theme, one of Christie’s favorite plots. Along with
The Hollow (1946), this book has Christie’s greatest characterization, but here the detective story is not forgotten: the cluing is ingenious, and the identity of the murderer is a brilliant shock. A deep, fascinating book, which should be required reading for all of AC’s detractors.
4.
The Pale Horse (1961): one of her best, fun and spooky, with witchcraft right around the corner. I suspect this is AC’s tribute to
John Dickson Carr (she was thinking of her fellow detective-writers around this time, as we know from 1963’s
The Clocks), just as
One, Two, Buckle My Shoe (1940) seems her tribute to
H.C. Bailey (I would have loved to have seen a tribute to Ellery Queen!

). The hero-narrator, the heroine involved in the mystery, the witchcraft background, the apparent impossibility of the crimes–these all seem Carrian, albeit filtered through Christie’s own style and sensibilities. The method is brilliant, and the murderer’s identity is diabolically clever. Some readers may long for Poirot, but I felt the team of Insp. Lejeune and amateur Mark Easterbrook more than make up for his nonappearance here.
3.
The Murder of Roger Ackroyd (1926): her first masterpiece, maybe still her most daring (or most foolish, depending on how you look at it) solution. There are a number of likable characters, ranging from narrator James Sheppard and his sister Caroline (the latter a proto-Miss Marple) to the Ackroyds and Capt. Paton and the rest of them, and Christie fools us with our presumptions about detective stories. Some revisionists (and Robert Barnard) consider this only a mediocre and traditional Christie, but can anyone deny the sheer shock value of the twist, her most surprising? And, even considered apart from that twist, no one can compete with the masterful juggling of times and alibis.
2.
Ten Little Niggers/
Ten Little Indians/
And Then There Were None (1939): my first Christie–wow. The characterization is brilliant, the story is beautifully told and captivating, and the murderer’s plot is ingenious. This is a story of human beings trapped alone on an island with their consciences and their emotions, all of them murderers and one of them the murderer–a mad agent of perhaps divine judgment. Far, far better than any of the movies based on it; the end chapters, before the murderer’s confession, are tenser than almost anything Christie ever did, with the possible exception of
Endless Night, and marvellously written. Read it.
1.
Death on the Nile (1937): “What can one say about perfection itself?” mystery critic Nick Fuller asks rhetorically in
his review. Well, what can one say that hasn’t already been said? It may well be the best detective story of ’em all, with undoubtedly the greatest alibi of ’em all–so simple, so smooth, and yet so undetectable until Poirot reveals all. The plot and characters are convincing and memorable. Though all of the characters are well-drawn, the plot hinges around the triangle, one of Christie’s favorite themes, and this is her best use of it. We are shocked by our preconceptions–not about detective stories, as with
Roger Ackroyd (or
Hercule Poirot’s Christmas), but about human relationships. Her masterpiece.