The work "Diachronic Criminal Law" deals with issues of diachronic law arising from the simultaneous enactment of the new Penal Code and Code of Criminal Procedure. It attempts to doctrinally approach the temporal boundaries of the provisions of substantive and procedural criminal law and to record the axes based on which the arising issues should be resolved. Additionally, it attempts to apply to a wide range of individual problems, which concern both theoretical dialogue and case law practice. It is addressed to anyone involved with criminal law (students, lawyers, judges, prosecutors, theorists).