This book reports the findings from the tri-national video study Quality of Instruction in Physics (QuIP). Within the scope of the QuIP study, physics instruction was investigated in a total of 103 classes from Finland, North Rhine-Westphalia (Germany) and German-speaking Switzerland. The main aim was to identify typical patterns of physics instruction of the three samples and to investigate conditions under which these patterns are successful with respect to students’ learning, interest and motivation. Among others instructional characteristics, the quality of students’ practical work, successful patterns of sequencing, the Subject matter structure and teaching strategies were investigated by means of analyses of video-recorded lessons.