This book contributes to the European-wide discourse on how to enhance the effectiveness and the practical implementation of the Directive 2014/41/EU on the European Investigation Order in Criminal Matters of the European Parliament and of the Council of 3 April 2014 (EIO). Through national reports (Part I), the analysis of selected topics (Part II), and shorter case comments (Part III), the book’s objective is to equip target groups with specialised knowledge about the cross-border evidence gathering procedure described in the Directive 2014/41/EU.