#58: The Problem of the Green Capsule, a.k.a. The Black Spectacles (1939) by John Dickson Carr

Green CapsuleMarcus Chesney doesn’t have much faith in human observation.  To prove his point, he arranges to put on a short demonstration for three witnesses, after which he will ask them questions about what they saw – secure in the knowledge, he says, that they’ll get the answers wrong.  The demonstration goes ahead, as part of which a disguised figure enters the room…and poisons Chesney in front of everyone before vanishing.  It swiftly becomes apparent that the murderer must not only be responsible for a spate of recent poisonings in the village but must also have somehow been one of only four people.  The only problems are that one of them has a rock-solid alibi and the other three were all watching the performance…

Into the aftermath of this sweeps Detective Inspector Andrew Elliot, protegé of Carr’s usual go-to policeman David Hadley, and struggling with his own moderately-compromised perspective on the crimes.  He has three excellent witnesses who were all in prime position to see what went on and so are able to tell him exactly what has happened…and their recall of almost every key detail differs.  All he has to do is somehow untangle this mess to catch not just Chesney’s murderer but also the person responsible for the previous crimes.  Thankfully, a certain Dr. Gideon Fell is holidaying nearby and has some time on his hands.

The Problem of the Green Capsule is one of the books that really highlights how lucky we were to have John Dickson Carr.  Plenty of poor plots have been told in marvellous prose, and vice versa, but Carr excelled at every single angle: take away the superlative writing, the expert pacing, the unshowy revelations casually unveiled throughout rather than stored all for the bumper final chapter – remove all that – and you’re still left with the brilliant realisation of Marcus Chesney’s demonstration.  It looks simple, it sounds simple, it is simple, dammit, but as you progress further through things Carr slowly belies this setup with genius touch after genius touch and you just have to shake your head in wonder.

Fell enters proceedings just before the halfway mark, by which time practically all the pertinent information has been revealed.  And yet there are revelations aplenty to come – Carr certainly isn’t short-changing you with depth and richness here, and if the contortions of, say, The Peacock Feather Murders seem a little too convenient for your liking then you may find this more suited to your tastes: it is a beautifully uncluttered, clear-sighted, whip-smart, and swift piece of devilry that honestly gets better and better as it goes.  I am now just under halfway through Carr’s 80 novels and short story collections, and I can believe that after the remaining 40 are done this will still be in my top five (and the blogosphere’s resident Carr experts TomCat and Puzzle Doctor similarly rate it very highly).

I don’t want to say any more about the plot, there’s already more than enough here, so I’ll take a bit of time to admire Carr’s authorly authority (no spoilers, of course).  The clues are abundant and regular, but the most impressive aspect is how the one crucial thing that has dated the most – something probably fully understood at the time, but having passed into obscurity many years ago – is still explained, highlighted, waved under your nose and given to you in no uncertain terms and you’ll still probably miss it.  A good counter-point is the ‘spot of grease’ on the passport in Murder on the Orient Express: that doesn’t translate these days because passports have changed.  Well Carr has arguably pre-empted such a problem of a key clue and simply covers himself beautifully, ensuring its relevance for the ages.

And then of course there’s his written expression; from simple descriptions such as a man’s hair being described as ‘wirish grey…standing up in humps and angles which sixty years’ combing had been unable to subdue’ to the impossible setup relying on ‘a fiction-writer’s nightmare – a clock that could not be tampered with’, he throws in casual turns of phrase that stick in the mind perfectly.  He also sets tones and scenes perfectly:

Whoever said that it is always raining in Bath basely slanders that noble town, where the tall eighteenth-century houses look like tall eighteenth-century dowagers and turn blind eyes to trains or motor-cars.  But (to be strictly accurate) it was pouring torrents on this particular morning.

And, of course, every line and action of Gideon Fell – from his robust cavils of just about anyone in sight to his questioning a chemist about poisons ‘like a man enquiring after drainage’ – only serves to enhance that gargantuan creation further.  You even get a lecture on real-life poisoners to rival The Hollow Man’s treatise on locked room murders.  As a novel of detection it is simply triumphant, and further proof that Carr is unjustly neglected today; I urge you to track this down at the earliest opportunity.

star filledstar filledstar filledstar filledstar filled


Black Spectacles

The good news is that no longer need you scratch around for overpriced, poor condition secondhand copies of this frank masterpiece — in my estimation perhaps the pinnacle of the genre’s output. As of March 2023 it is being reprinted in the increasingly excellent British Library Crime Classics range, raising the distinct possibility that — along with titles put out by the American Mystery Classics range and three books reprinted by Polygon Books — we might actually be getting something of a Carr renaissance. With any luck, The Punch and Judy Murders (1936), The Four False Weapons (1938), The Reader is Warned (1939), and other masterpieces will soon follow, adding to the masterful The Seat of the Scornful (1941), She Died a Lady (1943), and Till Death Do Us Part (1944), as well as the hugely entertaining Henri Bencolin novels, we’ve already been fortunate enough see come to public awareness. Many thanks to all involved in making this happen; keep up the excellent work!

27 thoughts on “#58: The Problem of the Green Capsule, a.k.a. The Black Spectacles (1939) by John Dickson Carr

  1. Completely agree – this is by far Carr’s best “tricksy” book. There are others that I enjoy more that are more straightforward – Constant Suicides, Til Death Do Us Part – but they feel more standard GA fare with an impossible crime thrown in. This has Carr written all over every page. And one of the best hidden killers in all of his books.

    Liked by 1 person

      • I agree with Puzzle Doc: Green Capsule is not your typical, dime-a-dozen GA mystery novels and the only detective story that could serve as comparison material is Agatha Christie’s Cards on the Table, but I think Carr’s version is (of course) the superior one.

        Liked by 1 person

        • That’s a very apt comparison, and not a connection I’d drawn. And, of course, the nature of the solution here is far, far superior to Christie’s (I’ve never been a fan of CotT…though everyone else seems to love it, so I generally keep this to myself).


  2. I agree.
    I regard it as a brilliant novel, One of Carr’s best.
    A person is murdered in presence of several witnesses and a movie camera, yet no one is able to tell who did it!
    The plot is really ingenious. Though elaborate, it is fully comprehensible. Also well clued.
    I would definitely put it in my top 5 Gideon Fell, the other 4 being He Who Whispers, The Hollow Man, Till Death Do Us Part, and The Mad Hatter Mystery


  3. You make this book sound really good, so when I next go Carr shopping it’ll be at the top of my list. Where would you place it in regards to The Crooked Hinge and The Case of the Constant Suicides? In March the TNBs are going to be doing posts on Carr, so I was wondering if you were going to do any posts on him, since he is an author you have read a lot of?


    • It’s a very different book to both Constant Suicides and Hinge, as Puzzle Doctor hints above. It is superior to both as a puzzle and in its realisation, but Constant Suicides is more fun and, I maintain, a far better place to start. This is just a wonderful example of how a simple idea properly explored can run and run in a detective novel, and it makes it look so simple even though we know full well just how agonisingly difficult this kind of thing inevitably is (were it that easy, everyone would be doing it!). Now I’m expanding my scope to OOP books, there are a few more Carrs I’d like to get reviews up for, as so many of his proper classics are now unavailable.

      As for the TNBs…perhaps, but I don’t feel I really have anything to add beyond my reading and enjoying the books – I lack the analytical skill that makes writing anything else worthwhile. But if I can do it for anyone I can do it for Carr, so I’ll certainly mull it over. Thanks for the reminder.

      Liked by 1 person

      • Well you’ve definitely convinced me to give TPOTGC a try and as for TNBs it doesn’t necessarily have to be a thematic piece, as from what I’ve seen and done the TNB blogger pieces include posts on the book covers, reviews of short stories or novels by the author in question, lists of books to try, books to avoid by the author. It’s very open as to what you contribute and you wouldn’t have to do one for every week of that month.


  4. I read this so long ago that I have forgotten everything except that I enjoyed it! I could actually reread it and we discover the killer again! The funny thing is, the first Carrs that I thought were published by Collier, and this was, I believe, published by Dell. The Colliers looked so impressive to me that I believed the Dell Carrs were supposed to be considered inferior. But that was not the case. See how the look of a volume can affect a susceptible young mind?

    Liked by 1 person

    • I know what you mean – there’s a current author whose books I’ve felt less enthused about since the jackets were redesigned…and I cant tell if my lack of enjoyment is purely stemming from those terrible, terrible attempts at art which grace the books or if the books themselves have decreased in quality. I mean ityubjectivity is subjective, but it’s gotten ridiculous now…


      • It never really bothered me with Christie covers. Obviously, the Tom Adams covers are special, but growing up in America I settled mostly for Pocketbook and Dell covers. What REALLY irked me was learning that Dell had freaking ABRIDGED the novels! I had to find the British copies just to get the full Christie experience, which led me to finding those wonderful images by Adams!


  5. Hmmmm. Ah. Hmmmm. Ah.

    Of all the Carr books I’ve read, this is the one that I very much want to rate higher than I actually do. As a mystery novel, I think it boasts of an exceptional puzzle that few come close to, not to say outstrip: its premise is intriguing, its puzzle is intricate, and the twists and turns of its detection process are compelling.

    But, argh, some of the dramatic scenes! I found one or two of them quite difficult to swallow, and the prose clunky at times. ‘Black Spectacles’ was the first Carr novel I read, and I would say the same for ‘Plague Court Murders’. But things got better for me from ‘Judas Window’ onwards. I thought the theatrics in ‘Constant Suicides’ was just about bearable’, and the theatrics actually worked well in ‘Emperor’s Snuff Box’ and ‘Till Death Do Us Part’.

    I think I should re-read ‘Black Spectacles’ – I think Carr has grown on me, and I might have a much more favourable impression the second time round.

    Liked by 1 person

    • What I find particularly interesting about this is that I recalled your dislike of some of Carr’s ramatic tendencies while I was reading it and was thinking it’d be right up your street! Ah, well, obviously I just don’t have a clear picture of your tastes re: Car just yet (though I totally get – I think – your issues with Plague Court, which is at times suffocatingly melodramatic, though not necessarily in a way that bothers me). Ho-hum, I’ll get it right one day… 🙂


      • Actually, ‘Black Spectacles’ is right up my alley insofar as its tricksy, post-modern, premise, as well as its intricately layered puzzle, are concerned. In fact, I would go so far as to say that ‘Black Spectacles’ boasts of the best mystery of all the Carr titles I’ve read, even the ones I give higher praise to on the whole (‘Emperor’s Snuff Box’/ ‘Constant Suicides’/ ‘Till Death Do Us Part’). So I think you have rightly predicted my tastes on this count. 🙂 Perhaps for me Carr’s theatrics needed some getting used to on my part, and perhaps I will enjoy ‘Black Spectacles’ more the second time round.

        The good thing for me is that I’ve left some of Carr’s best titles to the very last. ‘He Who Whispers’ and ‘Hollow Man’ are still sitting on my shelf, awaiting to be read…! *dances*


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