There’s this thing called an appositive. Feel free to forget that word, but remember the rule of commas associated with it. If the renaming or descriptive noun or noun phrase that accompanies the central noun is essential to the identification of that noun, you do not need commas. Examples:
– I am not a polygamist. My husband, Gilbert, gets all my ire. [In this case, there is only one husband, so his name is not essential to the definition. The husband is the one husband; there are no other husbands in this case.]
– I am a polygamist. My husband Gilbert gets all my ire. The other guys get a pass. [In this case, the husband named Gilbert is essential to the definition of husband, to distinguish him from John, Ted, and Arthur, my other husbands. Poor Gilbert.]
– My book Best Seller is a best seller, far outselling my other five books.
– My book, Best Seller, is a best seller, which is amazing, as it is my first and only book.
-There are a million famous authors. I met the famous author Joe Schmo the other day.
-According to narcissist Joe Schmo, there is only one famous author. I met that famous author, Joe Schmo, the other day.
-She is the founder of the girl band Girl Band. (As there are a million girl bands, there would never be any reason to put a comma between girl band and Girl Band. Nor should you ever actually use the term girl band, unless, of course, you are talking about Girl Band.)
Okay, go off and err no more.