In job and advertising work the name of the month and day and date are generally put in lower-case of the text letter.

This rule is not followed, however, in books.

When the heading of the letter is very long lower-case letters are preferable to small capitals under the general rules of taste which govern the use of types.

The salutation, _Dear Sir_, _Gentlemen_, or the like, does not need small capitals.

It is better printed in italic lower-case with a colon (not followed by a dash) at the end.