This is not an easy read, indeed the first forty pages or so make some of the most intense demands on the reader of any book I have ever read, but if you have a love of the mysterious, the obscure and the sinister it is well worth persisting with. The way the story unfolds is quite ingenious and you will, if nothing else, learn a huge amount of obscure history along the way.
The basic premise of the plot is actually quite simple: three editors in a Milan publishing house specializing in wildly whacky works on the mystical and the occult begin, for their own amusement, to make speculative connections between the various way-out theories put forward in the manuscripts submitted for publication. To their amazement it soon transpires that they might be on to something, something so important that their own lives are suddenly put at risk.
Eco clearly had great fun with this, throwing every crack-pot theory and esoteric religious belief into the mix. The Templars are there, of course, as are the Rosicrucians, the darker branches of the Catholic church and the Masons. The Hollow Earth theory is given a spin, Khabbala is discussed, Dr Dee puts in an appearance and the measurements of the great pyramids in Egypt provide the answers to nearly everything. It is all beautifully explained, so outlandishly implausible that maybe, just maybe, it has to be true......
For a novel which is primarily about obscure branches of knowledge and the play of ideas the characters are actually surprisingly well drawn: Casaubon, the narrator of the story wondering just what it is they have stumbled upon; Belbo with his melancholy sense of the colourful road not travelled; Diotallevi, mild and knowledgeable, getting slightly drunk on mineral water, and the mysterious Aglie, who appears to have all the answers. Or, perhaps, all the answers bar one...
If you're looking for something imaginative and challenging, something which could perhaps be described as the Da Vinci Code's immeasurably smarter brother, then this could be for you. Demanding, but well worth the effort.