For years we have read as if they were the faithful transcription of his word, the well-known lectures delivered by Michel Foucault in 1983 at the University of California at Berkeley. But they were only partial pieces, summaries, this edition includes for the first time in a complete version, that series of conferences that actually constitute a seminar on the concept of parrhesia, the Greek term that means saying everything and its relations with the truth and Courage. To this corpus is added an extensive lecture delivered in Grenoble in 1982. Unpublished in Spanish. What exactly is the meaning of saying everything is equivalent to talking about anything moderation and without restraint, without making a selection by interrogating texts from Greek and Latin antiquity, Foucault traces the uses and historical contexts of a discursive practice that is based on law and the freedom to express a truth even at the risk of generating anger, rejection or retaliation, thus within a program of history of thought already maturing in its studies on sexuality, insanity and punishment indicates the ethical and political weight of parrhesia to the extent in that it is in the antipodes of flattery or Demagogy and puts at stake the courage of those who for the good of their community dare to publicly state truths that can be unpleasant. Also with great expository clarity is the courage of the subject who can accept a frank and uncompromising exterior word about his own behavior.