My copy of this one is in a Penguin Modern Classic edition, with that seductive eau de nil spine. Maybe I'm just being impressed by the cover, but I think this is the first of the run that I would recommend even to those without much interest in the genre.
If it's not the cover, it might be the setting that's getting to me. We seem to have spent a lot of time recently in dingy, straitened parts of southern England, and so it's a pleasant change to be instead in the South China Sea in the post-war era. I really don't know as much about this time and place as I might, but the picture painted here is of a febrile set of countries, bubbling with revolutionaries of various kinds, jockeying for political and territorial position to take advantage of the inevitable withdrawal of British colonial power—but, importantly, safe and exotic enough to allow enterprise and attract tourists.
The plot concerns the arms of the title: an abandoned cache of weapons, discovered by a lowly Indian clerk, Girija. He wants to sell them. He needs a middleman, for which he enlists a fairly shady family of Chinese businessmen with connections around the Sea. The need a dupe to launder the arms and present them for sale to a group of guerrillas, for which they enlist an overconfident American cruise-tourist and his wife. The plot follows the progress of this convoluted deal.
There are two things that are done wonderfully as the plot unfolds, and these are the things that lead me to recommend the book widely. The first is structural. The book starts with Girija and ends with him, but in between the focus shifts further and further out from him, towards the Chinese and then the Americans, and then back again in the opposite direction. It's as if the book slowly takes in a big breath of air, holds if for a while, and lets it out again. It's a very, very neat structural trick if you can pull it off, and Ambler does.
His other neat trick is tonal. We start in a faintly comic mood, and we barely notice as things become more and more serious, until they're suddenly somewhere close to horrific. A lot of books (and perhaps even more films) aim for this shift, but don't manage it nearly as well; you can feel the wrench as the ratchet is turned. This is much more subtly done, more like that poor frog you hear of in the slowly heating water.
You can see from these two things why Ambler was highly regarded in his time and considered worthy of Penguin reissue today (my copy is from 2023, though whoever had it before me gave it quite some reading). Both Greene and Le Carré are mentioned in the blurb, and you can also see how he stands somewhat in between the two—the righteous adventuring of Greene dissolving slowly into the amoral stalemate of Le Carré (perhaps that's unfair. I really should re-read some of the tougher Greene).
One might worry that the combination of settings, peoples, and author (very much British, very much 1950s) would lead inevitably to a degree of stereotyping, if not outright racism, sufficient to spoil all the good things of the book. But I think Ambler still gets away with it. There certainly is national stereotyping, some vital to the plot, some not (there's a French character who seems only to be French to afford an opportunity to poke fun at the French), but it's not egregious for the most part, and it's probably the Americans who come off worst. In fact, at a couple of points, there is some subtle stuff about who is offended by what that shows at least some authorial awareness of how the sausage is being made. I even wonder if one could read the book as allegorical: it seems plausible that the preoccupations and preferences of the various characters are synecdochical for their nations' policies and politics in the region, though I would need to do a fair bit of reading to substantiate that hunch.
Anyway, the point is, one could find offence here if one were looking for it, but one can also certainly find a very well-structured, tonally assured, tightly written book. I enjoyed it very much and I certainly intend to read more Ambler. Give it a go if a copy comes your way.