The Trumpeter of Krakow's guiding spirit, a scholar named Jan (pronounced "yon") Kanty, is a Christian humanist. Kanty represents a clearheaded, essentially optimistic and scientific view of life; he fights superstition, ignorance, mindless respect for authority, and the dangerous habits and fears such attitudes breed. A Renaissance scholar in the making, Kanty is a precursor of the famous Polish thinker Copernicus, whose assertion eighty years later that the sun, not the earth, is the center of the universe will radically change the way people see their world.

The novel presents these issues largely through the eyes of its central character, Joseph Charnetski, the fifteenyear-old son of Pan ("Master") Andrew Charnetski, a Polish landowner driven from the Ukraine by Tartar raiders.

Joseph travels to Krakow, and through his eyes readers watch the broad sweep of medieval life; the crooked streets are filled with all levels of society...