p.s. The name of the letter's recipient is hyphenated because I have not named her yet.

Aelianus affixed the stamp to the letter, and dropped the sealed envelope into the mailbox. The contents of the letter would not be met with pleasure, he knew, but someone needed to speak out for the oppressed and exploited. He had appointed himself as the spokesman for his own misunderstood race. Smiling slightly - careful not to show teeth - his perfect memory allowed him to review the exact wording of his protest:

Dear Ms.___
I have read your books, and while you are a very talented writer, I feel it is necessary to inform you of a very serious problem I have with your work.
 

Aelianus affixed the stamp to the letter('a stamp' would do and not make the stamp more important than it need be.), and dropped the sealed envelope into the mailbox. The contents of the letter would not be met with pleasure, he knew, but someone needed to speak out for the oppressed and exploited. He had appointed himself (as the)(cut) spokesman for his own misunderstood race. Smiling slightly - careful not to show teeth - his perfect memory allowed him to review the exact wording of his protest:

'The' is probably the most invisible word in writing, but it jumped out at me in this. Mostly because it was used four times in the first sentence, the second sentence began with it and used it three times. Remove a couple of them and I wouldn't be bothered by them(My Personal Nit, MPN(tm).)

The fact that he is a vampire being mentioned in the first thirteen would make it more hooky. May I suggest:

I have read your books on vampires, and while you are a very talented writer, I feel it is necessary to inform you of some inaccuracies in your work.

We now know he has inside information on vampires, we still don't know he is one, so this is far from the best possible adjustment to be made be I am sure you can think of something better.

"Aelianus affixed the stamp to the letter, and dropped the sealed envelope into the mailbox."

-You could add some forward momentum easily here by changing and dropped to read dropping. "...to the letter, dropping the sealed ..."

"The contents of the letter would not be met with pleasure, he knew, but someone needed to speak out for the oppressed and exploited."

-I like this sentence. It gets your point across without slamming it into the reader's face. Nicely done. (Maybe move He knew to the front)

"Smiling slightly - careful not to show teeth - his perfect memory allowed him to review the exact wording of his protest:

Dear Ms.___
I have read your books, and while you are a very talented writer, I feel it is necessary to inform you of a very serious problem I have with your work."

-I think using his perfect memory as a vehicle for displaying an entire letter to the reader may expose your intentions as a writer a bit too obviously. As a reader, I'd prefer to see one of two things here: 1. Rewrite the scene so the vampire is reviewing the letter *before putting it in the envelope. 2. Don't show the letter at all, simply have him remember the good parts. Unless the memory ability is a key element of the story later on, in which case I could see it being a nice tactic. That way it would add credential to his later use of the ability. I just want to say - careful here - seeing the "
his perfect memory allowed him to review the exact wording of his protest:" made me think "okay, the writer wants to lecture about some crucial details, but doesn't want to do it through the character" -- I am constantly cleaning up after myself when it comes to that mistake (I'm always lecturing the readers )

 

Andrew, excellent advice. I haven't decided yet wether his recall will be important later, although it may. Begining with his letter was my origional instinct. It sounds like posting a couple of versions would be well worth my time.