The Lone Sentinel is a novel about growing up. Like many teen-agers, both Erik and Augusta consider themselves adults—Erik because he is always careful to do his duty, and Augusta because she loyally protects her sister. To achieve true maturity, however, each must gain a more balanced perspective. Erik must learn to make judgments for himself and sometimes to break the rules. Augusta must learn that her responsibility extends beyond the well-being of her immediate family, that she also owes a duty to society as a whole.

A secondary theme is loneliness.

Until his father's death, Erik has never realized the extent of his isolation.

Alone in the compound, Erik imagines that he hears a voice calling his name, and when Thursday responds to the howling wolves, he faces the unendurable prospect of being completely alone. He both fears and welcomes the...