How many ways can you arrange the books on a shelf if the books are grouped by author?

ralph sampson: How many ways can you arrange the books on a shelf if the books are grouped by author?
You have 7 different books written by Tom Clancy, 4 different books written by Louis L’Amour, and 5 different books by Isaac Asimov. How many ways can you arrange the books on a shelf if the books are grouped by author?

Answers and Views:

Answer by tigerlover786
Put the authors in Alphabetical Order
Put them in the order you like them
Put them in the order of which you intend to read them (or the order you read them in)

Answer by MichelleB
Put them in order by:

alphabet (author first names)
alphabet (author last names)
alphabet (book title)
book height
book color
favorite to least favorite
genre
publication date