Leon.. I confess that I couldn't understand your phrase (when trying to translate it)
Kjedelige is the plural form
Bøkene er kjedelige ~ the books are boring. Boken er kjedelig ~ the book is boring.
I hope this helps! If you have more questions, feel free to ask me:)
You could say "Den kjedelige boken er kjedelig", so you'd use the indefinite form when it's not in front of the noun.
This must be about Crime and Punishment. The crime was Dostoyevsky writing it and the punishment was having to read it.