You're interested in a deep feature on Donna Tartt's "The Little Friend" but in Italian, and possibly in a PDF format. However, I noticed that the book you mentioned, "Dio Di Illusioni" (which translates to "God of Illusions"), seems to be a different title.
Published in 2002, "The Little Friend" is Donna Tartt's second novel, set in a small town in Mississippi. The story revolves around a young girl named Mattie Dog, who embarks on a journey to find her missing brother. The novel explores themes of family, trauma, and the complexities of human relationships.