This book develops principles of proper sentence justification, presents results of comparative empirical study on sentence justifications in the post-communist countries and provides practical measures to improve the current situation. Providing justification for sentences is an essential feature of any sentencing system that strives to achieve principled practice. Principled sentencing requires factors to be considered as well as explained both individually and comprehensively, in a manner that allows the process of determining the sentence to be reviewed and repeated with a similar result. This work determines why reasoning is relevant and provides compelling evidence in favour of an increased role for justification of sentences, grounded in the best sentencing, legal and psychological scholarship. It further explores how various theoretical and practical obstacles might be overcome. Relatedly, it introduces and expands on Schuyt's novel concept of justifying sentences, which approaches sentence justification in three stages. The authors investigate to what extent these stages are followed in practice in the Czech Republic, Estonia, Moldavia, Slovakia and Slovenia. The results suggest that the quality of sentence justification in these countries is generally low, although there is some variation. The book concludes with suggestions for improving the process and quality of sentence justification. The work will be of interest to those working in the areas of Criminal Law, Criminology, Comparative Law and Legal Philosophy.