Last Ditch has a style variation that appears to be the author's; I don't think it was a house style choice, but I could be wrong, of course. :]
On pages 206-207, there are two styles used:
- "Doctor Carey" when beginning a paragraph of narrative;
- but "Dr. Carey" when otherwise used in narrative
Why does this matter? Well, I didn't notice it myself until it was in two pages facing each other. This may have been a house style choice, it may not have, it's hard to say.
But I wonder. If this had been a job, I would have queried this.
Style choices matter. They'll be invisible to some readers, and not to others. Certainly this style question didn't wreck my interest in the mystery, but when confronted by the difference, I marked it. :D
In case you're curious, I read the hardcover edition from Little, Brown (1977).