[From The Vagrant Mood, Doubleday & Company, 1953 [1952], “The Decline and Fall of the Detective Story”, pp. 123-30:]

[The story of pure detection] has been replaced in the public favour by the "hardboiled" story. This is said to have been invented by Dashiell Hammett, but Erie Stanley Gardner claims that the first to write it was a certain John Daly. In any case it
was Hammett's The Maltese Falcon that created the vogue.

[…]

"Dashiell Hammett," as Raymond Chandler says, "gave murder back to the kind of people that commit it for reasons, not just to provide a corpse, and with the means at hand, not with hand-wrought duelling pistols, curare and tropical fish. He put these people down on paper as they are, and he made them talk and think in the language they customarily used for their purposes." This is high praise and it is justified. Hammett had been for eight years a Pinkerton detective and he knew the world of which he wrote. It enabled him to give a plausibility to his stories which has been equalled only by Raymond Chandler himself. In the novels of this school actual detection takes a relatively minor place. No great secret is made of the murderer's identity and the interest of the story depends on the detective's efforts to fasten the guilt on him and the dangers he incurs while doing so. A consequence of this is that the writers have discarded the tiresome use of clues. In fact, in The Maltese Falcon, Sam Spade, the detective, pins the murder of Archer on Brigid O'Shaughnessy by pointing out to her that she is the only person who could have committed it, whereupon she loses her presence of mind and admits it. If she hadn't done this, but had coolly answered ''Prove it," he would have been nonplussed; and in any case had she got Perry Mason, Erie Stanley Gardner's astute lawyer to defend her, no jury would have convicted her on the flimsy evidence which was all that Spade had to produce.

[…]

Dashiell Hammett is an inventive and original writer. Unlike the authors who use the same detective over and over again, he has created a different one for every story. The detective in The Dane Curse [sic] appears to be a fat, middle-aged man who depends on his wits and his nerve rather than upon his brawn; Nick Charles in The Thin Man has married a wife with money and retired from the business, which he resumes only on pressure; he is a pleasant fellow, with a sense of humour; Ned Beaumont in The Glass Key, a professional gambler and only a detective by accident, is a curious, intriguing character whom any novelist would have been proud to conceive; Sam Spade, in The Maltese Falcon, is the best of them all and the most convincing. He is an unscrupulous rogue and a heartless crook. He is himself so nearly a criminal that there is little to choose between him and the criminals he is dealing with. He is a nasty bit of goods, but he is admirably depicted.

Sherlock Holmes was a private detective, but the authors who came after Conan Doyle seem to have preferred to solve their mysteries by means of a police inspector or a brilliant amateur. Dashiell Hammett, having been himself a private detective, very naturally used private detectives when he came to write stories and his successors in the hard-boiled school have very wisely followed his good example. The "private eye" is at once a romantic and a sinister figure. Like the amateur, he can be cleverer than members of the force and he can do things, mostly shady, which they are by law forbidden to do. He has the further advantage that, since the district attorney and the police regard his unorthodox methods with suspicion, he has to fight them as well as the criminal. It adds tension and dramatic conflict to the story. Finally he has the advantage over the amateur detective that, as it is his business to deal with crime, he cannot be regarded as a busybody who pokes his nose into what is no concern of his. But why he has adopted this unsavoury profession we are not told. It does not appear to be a lucrative one, for he is always short of money, and his office is small and poorly furnished. We are told little about his antecedents. He seems to have neither father, mother, uncles, aunts, brothers nor sisters. On the other hand he is fortunate in having a secretary who is blonde, beautiful and loving. He treats her with kindly affection and now and again rewards her devotion with a kiss; but so far as I can remember is never so far carried away as to make her a proposal of marriage. Though (with the exception of Chandler's Philip Marlow) we are not told where he comes from nor how he acquired the knowledge to pursue his avocation, we are told a good deal about his person and his habits. He is irresistible to women. He is tall and strong and tough, and can knock a man out as easily as we can swat a fly. He can take any amount of punishment without permanent injury, for he has more courage than prudence, and will put himself, often unarmed, in the power of dangerous criminals who beat him up so brutally that you are astonished to find him up and about in a day or so apparently none the worse for it, and he will take risks so hazardous that you hold your breath. The suspense, indeed, would be unbearable if you did not know that the gangsters, crooks and blackmailers who have him at their mercy dare not riddle him with bullets or your novel would come to an untimely end. He has remarkable power of absorbing hard liquor. In the drawer of his desk there is always a bottle of rye or bourbon which he gets out whenever he has a caller and whenever he has nothing else to do. He keeps a flask in his hip pocket and a pint in the glove compartment of his car. The first thing he does when he arrives at an hotel is to send the bell-boy for a bottle. His staple diet, like that of most Americans, has a certain monotony about it and consists for the most part of bacon and eggs or steak and "French fried." The only "private eye" that I can remember who cares what he eats is Nero Wolf [sic], but he is a mid-European and his un-American addiction to succulent victuals, like his passion for orchids, must be ascribed to his foreign birth.

[…]

To my mind the two best novelists of the hard-boiled school are Dashiell Hammett and Raymond Chandler. Raymond Chandler is the more accomplished. Sometimes Hammett's story is so complicated that you are not a trifle confused: Raymond Chandler maintains an unswerving line. His pace is swifter. He deals with a more varied assortment of persons. He has a greater sense of probability and his motivation is more plausible. Both write a nervous, colloquial English racy of the American soil. Raymond Chandler's dialogue seems to me better than Hammett's. He has an admirable aptitude for that typical product of the quick American mind, the wisecrack, and his sardonic humour has an engaging spontaneity. […] Dashiell Hammett and Raymond Chandler have created characters that we can believe in. They are only a little more heightened, a little more vivid, than people we have all come across.