This first volume is devoted to the plasma–material interaction processes and contains critical data assessments and data collections for all major particle–surface collision processes related to the partial recycling, impurity generation and material erosion in tokamak fusion devices. Apart from processes induced by particle impact, plasma–material interaction effects related to off-normal plasma events (e.g. disruptions, runaway electron bombardment) are also covered in this volume. A summary of the status of data information on these effects is also provided.