So let me get this straight:
bok = book
böcker = books
böckerna = the books
Because it says böcker, which means "books" - it'd be böckerna for "the books". :)
Like in German, there is no continuous form in Swedish. It will become clear in context.
What other words inflect similar to "book" for plural and definiteness ?
And to complicate it there is a tree called bok which has the plural bokar.