The idea for the Operation Primer series originated in a scienti? c study entitled “ Mental Training in Surgical Education” that formed part of a collaborative project between the surgical department of the University of Cologne, the Institute of Sports and Sports Sciences of the University of Heidelberg and the European Surgical Institute (ESI) in Norderstedt. The aim of the study was to evaluate the effect of mental training, which has been used successfully in top-class sports for decades, on surgical training. However, in order for mental training to be applied to surgery, it ? rst had to undergo modi? cation. In the course of this modi? cation, the ? rst Operation Primer was produced, the layout of which was largely adopted for the ? nal version presented here. In the last two years ? ve Operation Primers have been published in this series: Laparo scopic Sigmoidectomy for Cancer, Laparoscopic Sigmoidectomy for Diverticulitis, ® Thyroidectomy with Harmonic FOCUS , Laparoscopic Cholecystectomy and Stapled ® TM Transanal Rectal Resection with Contour Transtar Curved Cutter Stapler Procedure Set. Now you hold the sixth Operation Primer in your hand: Laparoscopic Total Mesorectal Excision for Cancer. The feedback has been overwhelming so far. We have received encouraging and motivating messages from all over the world. Operation Primers have been translated into other languages and we have had requests for specialities other than general and visceral surgery as well.