By what title should I greet assistant and associate professors in emails and letters? By what title should I greet assistant and associate professors in emails and letters? I study in the UK and for post-doctorands up to senior lectures one uses "Dear Dr. X", but for professors one uses "Dear Professor. X".
Assistant and Associate Professors in the US can be formally addressed by "Professor" or "Doctor/Dr.". There should be no offense given with either salutation, and either is appropriate.