Can I add or change the author of a PDF file in iBooks?
To be clear, Bryan Luby's and ReF's answers are both correct. I wanted to elaborate on ReF's answer for those who may have never used Automator before. This will allow you to change the the data for items in bulk.

Changing the Author


Open Automator and in the left-most dialog box select "Finder &amp;
Folders."
In the subtree dialog box just to the right, select "Get    Specified Finder Items" and drag this box to the top of the workflow    zone.
Inside the "Get Specified Finder Items" box select "Add..."    and choose the files you wish to modify.
In the left-most dialog    box select "PDFs"
In the subtle dialog box, select and drag "Set    PDF Metadata" into the workflow after "Get Specified Finder Items."
Inside the "Set PDF Metadata" box, check the Author and type in    the Desired name.
Click Run, the play button, in the top right    corner.
After this workflow completes you can add these files to    iBooks and the Author field will be correct.


If you have previously added them you will have to delete the ones where the Author didn't show up.

Changing the Title

Unfortunately, iBooks reads the title from the name of the file; rather than, the title contained in the metadata of the pdf itself. If you want to change this is Automator it is possible. The most comprehensive way is as follows:


As above, use the "Set PDF Metadata" option to update the
metadata title to the title of the book.
From the PDFs subtree select the "Rename PDF Documents" widget to the end of the workflow.


This method will only work one file at a time and rename the file for you while updating the metadata. This is a particularly slow way to accomplish this task. It would be faster just to edit the file name directly in finder, or, preferably, use command line arguments and regular expressions to rename the file removing the unwanted parts.