This dossier “Systemic Thinking in preventive Human Rights Monitoring” was developed in the framework of the EU Project “Improving judicial cooperation across the EU through harmonised detention standards – the role of National Preventive Mechanisms”, implemented by the Ludwig Boltzmann Institute of Fundamental and Human Rights, in cooperation with the Associazione Antigone, the Bulgarian Helsinki Committee, and the Hungarian Helsinki Committee (see in this series, the Project Introduction of the Handbooks). One of the objectives of this Project was to analyze whether and how the principles and tools of a systemic approach can be used by National Preventive Mechanisms (NPMs) for enhancing their effectiveness and strengthening their role in preventing ill-treatment in prisons. This was done by presenting and discussing the approach with NPMs as well as applying the “systemic tools” during the Project workshops. While the Project proceedings clearly showed the potential of the systemic approach, it also brought to light the challenges and difficulties in making it applicable to concrete NPM work.