Eco's masterful novel is many things: a study of High Medieval Europe, a murder mystery, and a nested critique of scriptural literalism and inductive empiricism. Eco rejects both in favor of (no surprise) a semiotic analysis of signs.

William of Baskerville, Eco's Franciscan hero, is part William of Ockham, part Sherlock Holmes, and part Thomas Aquinas. With his scribe and protégé Adso, he travels to an unnamed Benedictine abbey to negotiate terms with a Papal delegation for the head of the Franciscan order to travel to Avignon.

These are difficult times for the Franciscans, who find themselves at the center of a maelstrom of controversy involving numerous efforts to reform the corrupt clergy. Various ascetic-minded orders find themselves folded into the orthodox position, like the Franciscans, or branded as heretics and burned alive, like the Cathars. The conflict between ecclesiastical poverty and wealth unfolds on the transforming landscape of Europe, in which the church vies for power with the Holy Roman Emperor, while both contend with the rise of the city and the university.

If your eyes are glazing over, you may not enjoy this book, because there is an enormous amount of historical, philosophical, and theological discussion of these issues. Eco is a prodigious scholar and his learning shows on every page, as his characters argue the details of scholastic debates on the merits of laughter, or recount Byzantine intrigues by this Pope or that. For anyone interested in this kind of thing, the breathtaking detail with which Eco depicts the intellectual life of the middle ages will be thrilling, and reason enough to read the novel.

These considerations form the backdrop for the main action of the plot, which revolves around the attempt by William and Adso to discover the author of a series of ghastly murders plaguing the abbey since their arrival, which appear to be somehow related to the legendary library of the monastery, one of the finest in Christendom.

The least satisfactory of the novel is Eco's critique of rationalism, which sticks out like an anachronistic sore thumb in his otherwise meticulously-contemporaneous philosophical rumination. Eco is not a great philosopher. His semiotic theory is superficially interesting but unproductive as a frame of reference, and his rebuttal of superstition in the face of empirical realism is far more persuasive than his rebuttal of empirical realism in the face of semiotics.

And so the story ends with a philosophical whimper where one would hope for a bang. Since this is the least-important and least interesting aspect of the novel anyway, it matters little. The historical richness and delightful intricacy of the plot are ample reward enough.