When first published, this first novel by semiologist Umberto Eco was a worldwide sensation.

Some 50 million copies of the book, including the translations, were sold. Movies were made of the central story.

But the story itself, its context and the underlying theme soon proved to be inaccessible to most readers.

I do not aim to solve all the book's philosophical meanings but just to scratch at the surface.

First some preliminary notes. The book is not measured in chapters but in the Church's sequence of liturgical hours - Matins, Lauds, Terce, Sext, None, Vespers and Compline.

From this it follows that the action is concentrated inside a big abbey that there used to be in North Italy, now a burnt-out ruin. 

Consequently too, almost all the actors were monks, including William of Baskerville and his assistant, Adso of Melk (the famous abbey just outside Vienna) who were outsiders in the story.

William, himself a former Inquisitor, had been sent to investigate a recent mysterious death of a monk, that looked suspiciously like a suicide. 

But there is a wider context. This is November 1327 and the Pope and the Emperor are at loggerheads.

The issue is: did Christ intend his Church to be poor as Francis of Assisi and so many revolutionary groups were saying? 

The Pope had just moved to Avignon and a confrontation between the two sides was to take place at the abbey and a delegation sent by the Pope was expected.

The Pope was insisting that the general of the Franciscans, Michael from Cesena, go and meet him. Meanwhile members of splinter groups were being condemned to be burnt alive - heretics like the Fraticelli, or the armed groups following Fra Dolcino and so many others.

Something evil was at work in the abbey and monks were beginning to die or rather be killed at the rate of one a day.

William had been chosen because he was a neutral figure between the two sides. He was respected by many and counted among his friends philosophers like Marsilius of Padua and William of Occam.

He was also a superior intellectual and the abbey's famous and mysterious library intrigued him.

It soon became clear there was an underlying sexual theme between some of the monks and also some of the monks had come from heretical groupings and were lying low at the abbey to avoid being caught up in the repression.

It is difficult to categorise the book: gothic novel, medieval tale, thriller, ideological allegory?

The book can be read in three dimensions - a thriller, which also includes long academic discussions, or a debate about ideas or a book about other books.

One final warning: don't waste too much time trying to understand the meaning and relevance of the title. It can mean anything and nothing at all.