Jehovah's Witnesses: Their Claims, Doctrinal Changes and Prophetic Speculation. What Does the Record

The publications distributed by the Jehovah's Witnesses often include grandiose claims for their organization. Typical are these excerpts from the July 1, 1973, WATCHTOWER:

...Jehovah's organization alone, in all the earth, is directed by God's Holy Spirit or active force...To it alone God's Sacred Word, the Bible, is not a sealed book....The only organization on earth that understands the 'deep things of God'! (p.402)

The April 1, 1972 WATCHTOWER adds:

Of course, it is easy to say that this group acts as a 'prophet' of God. It is another thing to prove it. The only way that this can be done is to review the record. What does it show? (pp. 197)

Do the published interpretations of Scripture and prophecy by this organization support these lofty claims, or do they reveal them to be merely the opinions and speculations of men? What does the record show?