The author of this work considers the experience learned perhaps more than anything else, saying that his experience as a criminal attorney candidate has taught him that the security of defense is not enough known nor applied in all its dimensions , so this book provides important ideas on the fundamental right and out in Mexican criminal law there is a gap between policy and practice, because for him there is an atavistic inquisitorial conception of the authorities responsible for safeguarding the rights of defense, complaint because the accused is treated as the subject of the proceeding, not as gifted subject of procedural rights, which translates into not giving the accused or his advocate equality of arms. Moreover, the author also claims that the right of defense, which implies knowing and being informed of the indictment, in Mexico is not respected in the preliminary phase, despite the constitutional reform on 3 September 1993 since in his view, these rights are originated and given the power to exercise it fully since there is a complaint, since the attribution of the results as a defendant in a legal status granted a privileged position for the innumerable rights I recognize the laws, however, there is no equality between the prosecution and defense. Finally. This text also refers to the practice that exists when the alleged accused cites as witnesses.