I just noticed this on a PBS book and thought it was just something that needed to be edited.  Then a few minutes later, I was at Harper Collins Website, and almost half the books there had it in the title too!  Does anyone know what it means?

It looks like it's short for "rack-sized" but doesn't belong in the title.  PBS gets a lot of it's book data from elsewhere, as do other sites, so sometimes the same error will propogate itself on lots of the book sites.  At least here we have people like you who notice stuff like this, and we can correct it!

If the information on a book listing in the database is incorrect...

A good place to check to see the real title is world cat.com.  You can often also see the title page itself on Amazon if you click on the "search inside this book" option.

And for ongoing great info on editing (and submitting book cover images), this is a great thread: Want to help with Data & Images? Find help here