This book focuses on the laws of the Church regarding the introduction, admissibility, examination, exclusion, and evaluation of proofs, with particular reference to ecclesiastical penal cases. For example, the burden of proof lies on the one who makes an allegation. (c. 1526). How does this fundamental norm play out during the preliminary investigation and during the penal process? This book addresses this and other rudimental questions such as the depositions of the accuser and the accused, the testimonies of witnesses, and the use of psychological expert reports in ecclesiastical penal cases. This book also treats the canonical norms concerning documentary proofs, judicial recognizance, presumptions, polygraphs, and other matters regarding canon law of evidence.