The reader who approaches this Manual of Ecclesiastical Law will find a wide range of subjects in which the juridical dimension of the religion unfolds: the channels of relation with the State, the guarantees of the profession in freedom, the education, the marriage , The media, etc. The origin of these sectoral regulations where the religious sphere has a unique treatment is, or should be, the right of religious freedom, as proclaimed in our Constitution. Even if such a statement is true, we must not forget that our historical past and the position of strength of the Catholic Church have conditioned the use of instruments of relationship, or the continuity of situations advantageous to that, which crystallize in patterns and institutions of the past. The normative set that derives from this reality can not hide certain contradictions with respect to the constitutional source. The quality of the Manual of the book carries the concern of its authors for the clarity in the exhibition, in order to make of it a useful instrument for university teaching. But this is not to the detriment of the interest that can be had for any person sensitive to the problems posed today by the legal treatment of religion and the holders of the right of religious freedom in Spain, whether these individuals or confessions.