Day fines as a pecuniary sanction have a great potential to reduce inequality in the criminal sentencing system as they impose the same relative punishment on all offenders irrespective of their income. Furthermore with correct implementation they can constitute an alternative sanction to the more repressive and not always efficient short-term prison sentences. Finally by independently expressing in the sentence the severity and the income of the offender day fines can increase uniformity and transparency of sentencing. Having this in mind almost half of the European Union countries have adopted day fines in their criminal justice system. For the first time this book makes their findings accessible to a wider international audience. Aimed at scholars policy makers and criminal law practitioners it provides an opportunity to learn about the theoretical advantages the practical challenges the successes and failures and ways to improve.