When I started writing, one of the standard rules of a novel was that the writer should tell the full name of a main or viewpoint character in their first viewpoint appearance. Mary may be Mary for the rest of the novel, but her first viewpoint scene should have her as Mary Smith in that first mention.
This rule seems to have fallen by the wayside in many of the novels I read, and that’s a pity.
I write mini-reviews of every book I read and share it with some of the reader lists I belong to, and I’ve spent lots of frustrating time trying to find a main character’s full name. Somehow, just a first name doesn’t seem enough when talking about a character to me.
Even more frustrating is an author who refuses to give any name to a viewpoint character. One well-known paranormal suspense writer has gone to the extreme in this. Her series is a paranormal version of CRIMINAL MINDS with psychic FBI agents and bad guys. Many of the characters have viewpoints in each novel, and members of the FBI team makes appears in some novels as minor characters with viewpoints. In an attempt to increase suspense or to be annoyingly coy, she will often not use the character’s name until late into the novel although who that character is doesn’t change anything when his name is mentioned.
This is so beyond frustrating that I want to grab her lapels and tell her to stop it.
One of the most important commandments of genre fiction is that the author does nothing to stop the reader in his tracks and jerk him out of the dream of the novel, and this kind of nonsense definitely does that.
Now, there are exceptions to always using a name. If your bad guy has a viewpoint and you don’t want to reveal his identity yet, it’s perfectly acceptable to identify him as “he” or some other way. Just be sure that the reader has some means of telling that “he” is the same person each time.