Do not have access to the Watchtower library, so I decided to research directly from the Society's website. Noticed that volumes are only good dating back to the year 2000. With all that has ever been written, why provide only from 2000 onward? Sure, there are references made to items published before then, but they are not accessible. Now some might argue that all this data would cost a fortune to store for accessibility, but due to the fact that we're talking about only printed text, I don't find that position defendable.
SOP