Gentleman,
I wish to apply for a position with your publishing house .I am XX years old and am at present employed by the Peterson Press, where I have been for the past five years. Formerly I was employed by the XXXXXX where I had been working for nearly five years.
My only reason for leaving either of those positions would be to better myself and I feel there is no further opportunity in my present position.
The editorial work has always had a great appeal to me as I have some ability in writing and editorial work.
I can give you references from both these press houses as to my character and ability as an editor.
Truly yours,
XXX