My Spanish is non-existent, but it looks like a decent alternative or companion to the likes of Maitland McDonagh in English or Jean-
First there's a thematic overview, identifying key motifs in Argento's films - e.g. the elements (agua), animals (gatos) etc.
Then there are chapters on each of his films through to The Phantom of the Opera.
Then there is a 1999 interview with Argento, conducted at the Sitges film festival.
Finally the are portraits of important collaborators such as Morricone, Goblin, Nicolodi and Cozzi.