VBA-SQL Syntax Error

What am I doing wrong?

Here's my commented code. I believe that I am not writing the If-Then statement correctly in this function. It appears to be generating a SQl Syntax Error when I try to load the SQl string into my QueryDef object.

Function BuildSQLString(strSQL As String) As Boolean

'This section of the form code should build up a SQL command from the data in my form.
'    The table name is fixed here (and assigned to the variable strFROM) because it will never change, in this case.
'     The form contains a checkbox called "chkSchool" and a combobox called "cmbSchool."
'     When chkSchool is enabled, the form reads whatever School Name is selected in cmbSchool.
'     This all works fine.

Dim strSELECT As String
Dim strFROM As String
Dim strWHERE As String
Dim qdf As QueryDef

strSELECT = "*.*"
strFROM = "[Library Books]"

'My problem appears to lie somewhere in this If-Then statement. It seems to result in a SQl Syntax Error.

    If chkSchool Then
        strWHERE = strWHERE & " [School Name] = " & cmbSchool
    End If

 
'This part should buildup the SQL string in iterative fashion into the complete SQL Command
        '
strSQL = "SELECT " & strSELECT
strSQL = strSQL & "FROM " & strFROM
If strWHERE <> "" Then strSQL = strSQL & " WHERE " & strWHERE

BuildSQLString = True

'When I then try to create a qdf (QueryDef and load the SQL string into it, then the SQL Syntax Error occcurs
'What is wrong with my If-Then statement?

End Function