There could be a space or some invisible character in the SQLBook. To find out the difference between the two variables do the following:
1) First remove the similar characters:
Dim diff AS String = Replace(SQLBook, BOOK, "")
2) Then check the ASCII code of the character left in diff:
Debug.Print Asc(diff)
EDIT As per your comment, the difference is a Carriage Return character which is used to make a new line. To get rid of it, use:
Replace(SQLBook, vbCr, "")