And is that even what it's called or how it's spelled?...  Anyhow someone explained it to me like this - a dramaturg is someone who makes sure that the script is relevant to the actual times and/or the characters cast for the show.  In other words if there's a line in the show referrring to a character who is fat and the actor playing the role isn't fat then the lines are deleted or changed to accomodate the reality of the situation.  Is that an acurate description?   And how does this affect  "you can't chage anything in a script for any reason without permission" thing?

DWolfman is correct.  A dramaturg is primarily the one who does the research on the play in question.

I've worked and studied with dramaturgs on productions and academically.  They are often a director's right hand man in many ways if the script has a lot of historical data or in depth research is needed.  I like to look at dramaturgs as researchers and historians.  If you're doing Shakespeare, a dramaturg is a great resource to have that can research period clothing for a designer, textual references, historical data, etc - anything in the script or in the production that may need to be explored and researched.  Many colleges are now offering MFAs in dramaturgy.  I've taken a few dramaturgy classes and will tell you their work is not easy - but very beneficial to a director.  We spent an entire semester researching M@cbeth.  We researched many phrases and references that weren't included in the annotations of the scripts and things that would be confusing to an actor or director.  As a director it's something that I try to do myself - but with some more challenging scripts like Shakespear and Brecht - a dramaturg would be wonderful to have on hand.  I'm actually looking into having a dramaturg on hand with my upcoming production of Charles Busch's Die! Mommy! Die! as it is set in 1967 and I would like to have someone on board to make sure all the designers are on a consistent page to capture the look and feel of 1967 and to get some historical information to share with the cast and crew so we all understand the genre. 

I have been fortunet enough to also work with a wonderful fellow. He has more theater/film experience in one fingure, than the entire company. Anyway, he discribed his role as dramaturg as "Professional pest to the director".

In truth he is the one to keep the director on track, watches for continuty glitches. If the director wants to make a change in the script he plays devils advocate to find out if that change is nessasary etc.

If you have access to someone that has the knowledge, and is also someone that you can work with they are an invaluble service to the director.