Ernesto Gastaldi is much better known as a screenwriter rather than a director. He’s responsible for some of the most tightly scripted gialli in that the plots may be ridiculous, but at least they are logically consistent. There is no random, mid-movie clue discovery that changes everything (such as the library book chanced upon in Deep Red or the hero suddenly remembering a detail of a killing). Gastaldi makes a point to call out Argento for this nonsense in many of his interviews and commentaries. As such, everything in Libido is there for a reason. There are four characters, all of whom have a steak in possibly inheriting the fortune of an S&M killer’s estate. It’s not the most intriguing mystery but it does keep you guessing as to who is gaslighting who and, as all involved are equally despicable, ends the only way it possibly could.