A sensation on publication in 1980, Umberto Eco's heady novel is, among other things, a murder mystery, a riff on the Book of Revelations and a meticulous recreation of medieval Europe, particularly of Benedictine monastic life in Italy. Littered with Latin phrases, philosophical arguments and religious arcana, this big book is emphatically not for the faint of heart (though the movie adaptation with Sean Connery is a bit less daunting). But Eco is an institution in Italy (the first professor of semiotics at the University of Bologna, Europe's oldest), and readers who feel up to a challenge won't regret reading this great book.  (ITL413, $15.00)