The Welsh criminal justice system is unique. While the country has its own devolved government and parliament, there is no Welsh equivalent of the Scottish or Northern Irish justice systems. Rather, the writ of England and Wales criminal justice institutions continues to run. Yet the extensive responsibilities of Wales's devolved institutions ensure that they necessarily play a significant role in criminal justice. As a result, the Welsh criminal justice system operates across a 'jagged edge' of devolved and reserved powers and responsibilities. This book provides the first academic account of this system. It demonstrates not only that Wales has some of the worst criminal justice outcomes in western Europe, but that even if the will existed to try to address these problems, the current constitutional underpinnings of the Welsh criminal justice system would make it nigh-on impossible. Based on official data and in-depth interviews, this is an urgent and challenging book, required reading for anyone interested in Welsh politics and society.