If you are writing to someone who has a doctorate or medical degree, use the abbreviated form: "Dr." However, for other titles, such as professor, judge, rabbi, etc., write out the full title and capitalize it. For example, your salutation in a letter to a judge would be, "Dear Judge Barnard." Or, if your correspondence was with a rabbi, you might write, "Dear Rabbi Williams."
Salutation: (Two lines below the recipient’s address, or about 1Ǚ down the page) The person the letter is intended for. Avoid “Dear Sir/Madam” and especially “To Whom it May Concern” unless absolutely necessary; not directing a letter to an exact recipient suggests that you don’t care who reads it (or you would have made a call or checked their website) _ and may prevent the letter from reaching someone who can act on your letter.