I have now read all Carlos Ruiz Zafon's books, and must admit I am desperate for him to write another. He conjures up the past, and visions of evil so well that it is a surprise to find La Sombra Del Viento has a human outcome, especially after the malevolent Angel of the prequel! The links between this and it's prequel, El Juego Del Angel are fascinating, but not overstated.
As others have said it cannot be put down, and also as others have said please read it in Spanish if you can. And dont miss CRZ's earlier 'childrens books', El Principe de la Niebla, El Palacio de la Medianoche, Las Luces de Septiembre and Marina. If those are 'childrens books' then many a Spanish child must have had sleepless nights!