"I never met [Dashiell] Hammett and never corresponded with him. Here are some small and unimportant ways in which our lives touched. Hammett and I were both discharged from the Army in September of 1945 at Fort Dix, NJ. I was 29 and he was 51.
"His first novel, Red Harvest, was published in 1929 when he was 33. My first novel, The Brass Cupcake, was published in 1950 when I was 34. Both novels are still in print.
"His last short story in the pulp magazine Black Mask was "Death and Company," published in 1930. Seventeen years later, my first story in that magazine was titled "Manhattan Horse Opera," which doubtless shows a smidgen or two of the Hammett influence. He influenced us all: The straight, simple prose style. Everything deleted except what moved the action forward. Characters shown through action and through dialogue -- with a special emphasis on making the dialogue ring true. This is a very chancy area. You cannot have people talking the way people actually talk. Transcribe a tape of any casual conversation, and you will see what I mean. You have to do dialogue that, if spoken exactly as written, would sound just a little bit stilted -- yet on the page, it creates for the reader the imitation of a total reality."
-- from John D MacDonald's book review of Shadow Man (a Hammett biography) published in the August 2, 1981 edition of the Washington Star.
A similar sentiment was expressed by Raymond Chandler, when the problem was reversed. From a letter to James M. Cain dated March 20, 1944:
"A curious matter I'd like to call to your attention -- although you have probably been all through it with yourself -- is your dialogue. Nothing could be more natural and easy and to the point on paper, and yet it doesn't quite play. We tried it out [while writing the screenplay for Double Indemnity] by having a couple of actors do a scene right out of the book. It had a sort of remote effect that I was at a loss to understand. It came to me then that the effect of your written dialogue is only partly sound and sense. The rest of the effect is the appearance on the page. These unevenly shaped hunks of quick-moving speech hit the eye with a sort of explosive effect. You read the stuff in batches, not in individual speech and counterspeech. On the screen this is all lost, and the essential mildness of the phrasing shows up as lacking in sharpness. They tell me that is the difference between photographic dialogue and written dialogue. For the screen everything has to be sharpened and pointed and wherever possible elided."