It is actually sorted by title, alphabetically, 777 being the title of the first, The Basic Writings of C.G. Jung being the second, and Battlefield Earth the third, etc.
Click on that little blue link next to "Display Styles" A B C D that says "edit".
You should see a list with dropdowns where you can choose what columns are viewed. You should be able to choose Title for one, in whichever position you like, etc. To change what criteria it is sorted by, you click on the column header, sort of how you would in other Microsoft applications. When you add the Title column, I suspect you'll see the little blue arrow on the column header pointing down. Click it and it will resort the other way.
It is odd that it should sort it by a column you're not viewing though.