(Even as Margaret was urging her gifted husband to write mainstream fiction instead, Millar was telling his capable wife she made a mistake by limiting herself to suspense: "What nonsensical compulsion makes you suppose you must always write mysteries, when you can outwrite, outthink, and out-observe nine-tenths of the bestselling straight novelists now writing?… Why your absurd humility towards the novel form, which is exploited so successfully by your inferiors?")
Kenneth Millar's mystery-writing career (and no doubt his confidence) got a big boost in January 1946 when he received word from Margaret that one of his stories (which one, not yet known) had won a $300 Fourth Prize in the Ellery Queen contest. Millar guessed (correctly) it was "Death by Air." "The chief reason I'm so pleased," he wrote his wife, "… is that it makes it so certain that I'll be able to turn pro without any strain." He was also happy to note: "Dannay is bringing out all the prize winners in a book (good publicity for me… among detective fans!)" Millar consoled his wife on her own entry's failure to snag a prize: "You needn't feel badly about your story — as I said it was much too good for that market." (William Faulkner's EQMM submission took second-place honors.)
In the wake of his prize-winning entrance into the mystery-writing community, Millar chose next to read S.S. Van Dine's bestselling 1927 detective novel The "Canary" Murder Case, featuring sleuth Philo Vance. "Not a bad puzzle," Millar allowed in a letter to Margaret, "but the writing doesn't pass muster. Dreadfully pretentious, to cover up lack of knowledge about people and their feelings. Deadly slow and insufferably snobbish. Not as good as [Margaret's 1941 debut book The Invisible Worm], I think. Yet it's gone through 20 or so editions. There's one field where it paid off to be a pioneer. One similarity to Raymond Chandler: the masses of detail, which fill up most of the wordage. But unlike Raymond, there isn't enough action, drama, or character to make a good novelette. And if you think I can't write dialogue, try some more Dine. He writes the way I talk when I'm trying to be funny in a queer academic way. French and Italian phrases average one or two a page, and one of them at least is a hideous boner." (Later in this letter, after some highflown sentences about public and private virtue, Millar exclaimed: "Gracious, I'm getting serieux, ma cherie, as Philo Vance would dicere, n-est-ce pas?") Reader Millar abandoned Van Dine for a book by psychologist William James.
The almost cruise-ship calm of the Shipley Bay in the waning weeks of now-Lt. j.g. Kenneth Millar's postwar Naval service was broken the evening of January 18, 1946, by the Shipley Bay's participation in a rescue at sea of the thirteen-man crew of a downed flying boat. "It was a perfect night for a rescue," Millar reported to Margaret. "Bright full moon. Fairly calm sea." Mission safely accomplished, Millar sat down and for about ninety minutes made notes of some of his plot notions. "It appears that I have ideas for 20 books!" he informed his wife. "Maybe 10 of them are worth writing. Maybe 5 of them will be written (because by that time I'll have ideas for others…) Anyway, my postwar plan includes plenty of work…"
Again he wished he knew which of his stories Ellery Queen had bought: "It would give me something to go on with, since I'd like to write them another story or two (I have a couple ideas — plenty, in fact, since any ’tec. novel can be written a short story.)" In the next days he plotted two mystery shorts but refrained from writing them in his cramped shipboard quarters, in the tropical heat: "I don't want to force to much production under difficult conditions, for fear that will destroy my enthusiasm for writing, my élan, my passion in a word. I don't want to become (or continue as) a hack…
By February, Millar had at last learned which Joe Rogers story Ellery Queen had bought: as he'd suspected, it was "Death by Air," though the magazine gave it a new name. On February 12, Millar informed Anthony Boucher by letter of "a hard-boiled short (re-titled Find the Woman) which got me fourth prize and three C's (as they say in hard-boiled stories). I can say with certainty that I'd never have written it if you hadn't urged me to, so this is on the lines of a 'but for whom.' "
He also wouldn't have written it if Ellery Queen hadn't founded a magazine and given a contest. But whatever professional gratitude Ken Millar felt towards Ellery Queen, he didn't let it cloud the critical eye with which he read their fiction — a critical eye he needed to keep in sharp focus if he hoped to reach the artistic summit of his newly-chosen field. "Brought up [Queen's 1942 book] Calamity Town to read on watch," Millar wrote his wife in mid-February, "but boggled a bit after 2 pages… What a difference style makes. If a book hasn't got it I can read it only with difficulty, and EQ ain't g it, though how they try…"
… only one of the fifteen prizewinners in EQMM's first contest is classifiable as a hardboiled detective story. Even that one — Kenneth Millar's "Find the Woman" — is not a pure hardboileder. True, it presents in Rogers, the private dick, a Hammett-Chandler tough hombre; it offers a hard, realistic crime situation… And yet with all this, Kenneth Millar's story is not pure hardboiledism: its characters are not psychologically black-and-white, and there are undertones and over-tones in "Find the Woman" not usually woven into the fabric of tough ’tecs…Kenneth Millar's first book was The Dark Tunnel (Dodd, Mead), an excellent novel of suspense and pursuit in which the author "tried to treat a romantic and melodramatic plot in a realistic manner, with a hero who is not particularly heroic…" Those are Mr. Millar's own words and we wonder if they don't describe his short story, "Find the Woman," much more accurately and pointedly than your Editor has…
— Ellery Queen, Ellery Queen's Mystery Magazine, June 1946
Discharged from active duty in the spring of 1946, Ken Millar joined his wife and child in Santa Barbara, where he felt the urgent need to get a few books under his professional belt. His mostly-shipboard-written thriller The Suicides was bought by Dodd, Mead, to be published as Trouble Follows Me. (To the author's dismay, Dodd, Mead rejected The Suicides title as "not box-office.") Millar quickly wrote two more crime novels, Blue City and The Three Roads, which his agent sold to the much more prestigious publishing house of Alfred A. Knopf.
Millar also did some half a dozen mainstream short stories after the war — only one of which, after six months' submissions, was bought for publication. The pragmatic Millar learned a lesson: in future, he wouldn't spend time on short stories unless a viable market presented itself.
One did in 1948. Ivan von Auw at the Harold Ober Agency suggested Millar try writing a story for the American, a slick magazine with a predominantly female readership. Millar had met one of the American's former editorial workers in the Navy: the public relations man who'd cleared the plot of Trouble Follows Me. He'd told Millar what that glossy's "very successful editorial policy" was: "promising the readers sex (e.g. through illustrations) but not giving it to them. It always works — see also the movies…"