Ms.

definitely Ms.

If it's the editor of a journal, it may be Prof. Tanner.

She's not a Dr., they usually put that in their tagline.... assistant to the editor, actually, is her title.

Whether email or snail mail, I agree it should be "Dear Ms. Tanner:"
Definitely not Mrs, if you don't know her marital status. If she doesn't have Ph.D. or other such letters after her name, then Ms. is the way to go.

Ms., unless she has a PhD, then Dr.

If she also teaches, you could go with Professor, even if she doesn't have a PhD.

Ms. or sweetheart.

"Hey Toots" should score you some points.

Martha my dear,
though I spend my days in conversation,
please remember me.

I'd like to invite you over to my place for some home-cooked Indian food and a bottle of unpretentious wine. I'll only ask you to remember to hold your head up, you silly girl. When you find yourself in the thick of it, you'll want to help yourself to a bit of what's all around you, silly girl.

Take a good look around you. Take a good look and you'll see that you and me were meant to be for each other, silly girl. So when you find yourself in the thick of it, you'll want to help yourself to a bit of what's all around you, silly girl, but please don't.

Martha my love, don't forget me, Martha my dear.

Sincerely,
Your Pal YJ

P.S. Would you mind publishing my paper, babe?

@YJ: "Martha Tanner" isn't that usual a name. So, is she on LinkedIn? Is she on Facebook? Is she on the Electoral Role? Have you Googled her and the organisation she works for? The information you require will be out there.

@ghug you're an ass and I love you.

@STA it was more of a general question, I have wondered before. I was inclined to agree with the others, but part of me kept going "If she's a Mrs. and I call her Ms. then she'll feel like I'm condescending to her or something."

Ms., always. Miss could be taken as condescending, and Mrs. as presumptuous, but Ms. does not presume a marital status.

Ms. if you can't find more, but STA is right. Search the web and do your due diligence. You should be able to find out more. And even if you don't on the greeting, you might learn something that helps with the letter in general.

@ghug, one of the funniest things I've seen on this forum in a while, Lol

A strict first name basis is not uncommon in English speaking academic circles, and this includes publishers and editors , so why not "Dear Martha, ..."

Ms. for sure.

Should we call you Ms. Fox? Or do you go by Mrs. Fox-Hound (don't know hubby's nickname on here to do that right)?

MS. Fox would be fine with me if my marital status was unknown. I guess I go by Mrs but that situation hasn't really come up.

But are you just a Fox or a hyphenated Fox? My wife always hated her middle name so she officially dropped it, moved her maiden name to her middle name, and took my name as her last name when we got married. No hyphen, just Mrs. First Maiden Draugnar. Although for some reason (she's old fashioned) she likes Mrs Robert Draugnar.

I changed my last name to his but I really haven't had much mail with the changed name. We were in this apartment before we were married.

My wife kept her last name. (Who can blame her? My last name is Heck. It's not a name one would take, if given the option.) Also she's a PhD. So on mailings, we're always "Dr. W------ and Mr. Heck.

Yellowjacket: "Honorable Martha Tanner, Judge Presiding" should do. Thank a quick Google search for this insight:

http://quest.law.com/Search/Search.do;jsessionid=131E0B73AE2347F84FB4E1A9E8FB4FD4?D=%2522Honorable%2BMartha%2BTanner%252C%2BJudge%2BPresiding%2522&sortVar=1&Nty=1&Ntx=mode+matchallpartial%7Cmode+matchall&Ntk=SI_All&Ns=P_Date%7C1&Nr=OR(8338,8444)&N=0&cx=0&Ntt=%22Honorable+Martha+Tanner%2C+Judge+Presiding%22&Dx=mode+matchallpartial&site=tx&search=null

Her Excellency Martha Tanner, Ambassador Extraordinary and Plenipotentiary of the United Kingdom of Great Britain and Northern Ireland?

"Ms. does not presume a marital status"

It doesn't? I thought Ms. was the abbreviation of Miss, just as Mrs. was to Missus.

If you are speaking in person, "Yes Ma'am" and "No Ma'am" never hurt anyone.

Nope. Ms. is pronounced as "Mizz", which is distinct from "Miss".
http://en.wikipedia.org/wiki/Ms.

You do know that Ma'am is basically colloquial Madam which refers to one who owns a house of ill repute? Right?

Nah, Ma'am is short for Madam which is Frog speak for "My Lady". Best, therefore, to write the entire letter in the style of Parker from Thunderbirds

F.A.B

Damn it, Oct, I'm trying to troll here. Stop fucking up the works. :-)