Word contains a couple of different ways that you can adjust the case of selected text. If you are using Word 2007 you can make sure the Home tab of the ribbon is displayed and then clicking the Change Case tool in the Font group. If you are using an older version of Word you can click Format | Change Case to display the Change Case dialog box.

Either way, you'll see a list of different ways in which Word can adjust the case of your text. One of the most common case changes is title case. This type of change results in each word of the selected text being uppercase, while the rest of the letters are in lowercase. The only problem with this is that Word is rather indiscriminate in what it capitalizes. For instance, if you select the text "this is a test" and then use the Change Case dialog box to change the text to title case, you end up with "This Is A Test." Common rules of capitalization, however, would dictate that the "short" words ("is" and "a") should not be capitalized.

This is where a macro comes in handy. You can create a macro to intelligently apply title case to a text selection. The macro can be programmed so that it ignores a specific set of words while doing its work. Consider the following macro:

Sub TitleCase()
    Dim lclist As String
    Dim wrd As Integer
    Dim sTest As String

    ' list of lowercase words, surrounded by spaces
    lclist = " of the by to this is from a "

    Selection.Range.Case = wdTitleWord

    For wrd = 2 To Selection.Range.Words.Count
        sTest = Trim(Selection.Range.Words(wrd))
        sTest = " " & LCase(sTest) & " "
        If InStr(lclist, sTest) Then
            Selection.Range.Words(wrd).Case = wdLowerCase
        End If
    Next wrd
End Sub

When you select some text and run this macro, the first thing it does is to change the text to Word's standard title case. It then steps through the words in the selection (Word makes the words available in the Words collection), examining each one. Each word is extracted and placed in the sTest variable, which then is converted to lowercase. The contents of sTest are then checked against the lclist string to see if there is a match. If there is, then the word in the original text is converted to lowercase.

The key to the macro is the lclist string. This string contains a list of words that you want to always appear in lowercase. These words are surrounded by spaces—including the first and last words of the string. When the sTest comparison is done, sTest contains a leading and trailing space so that successful matches can be made. (The spaces are included so that there are no mistakes in word matching, for instance matching "he" to a part of "the".)

Note, as well, that the comparison portion of the macro doesn't pay attention to the first word in the text selection. This word is assumed to be the first word of a phrase or sentence, which should always start with an uppercase character.