Mosley utilizes mystery writing techniques to engross the reader. Teased foreshadowing hints at Tall John's origin and why he believes 47 is vital to the fate of his people and possibly all of existence. Readers greedily look on for answers, but forget what they were looking for because they get sucked in to the ensuing scene or plotline. Any reader will feel sympathy and concern for the believable characters, most of which are slaves.

This story is daringly planted around slavery with just enough brutality and violence to show the wickedness of slavery. If there were more than the handful of beatings and deaths that were in the story, 47 may not have been suitable for the recommended 12+ reading age. Such atrocities represent the darker sides of human nature and stress the need for freedom.

These themes, and the story as a whole, works best when speculative elements are subdued. Tall John's powers--among them: time alteration, healing, and foresight--are essential to the plot. However, descriptions of Tall John's home land, with bizarre colored skies and people and the evil race of giant albino heads, the Calash, intrude upon the story. This is also true of the thinly-developed alien villain, Wall, and his plot to mine the earth and infiltrate the "God- Mind" of Tall John's people, a higher plane of existence where everyone is equal.

These speculative pieces of the story (effective or otherwise) are powerful metaphors for the effects of the centuries-old acceptance of slavery, attaining freedom, gaining confidence, and demanding independence.