Much is similar in the Nordic countries. But much is also different. The purpose of this anthology is to study the Nordic countries from some different perspectives by using data from PISA 2006. How different are the curricula and syllabuses? Is the impact of socio-economic status different in different countries and for different groups of students? Are the Nordic countries more closely related to each other than to other countries? These are some of the questions studied and discussed. This publication is the third edition of Northern Lights on PISA. The first editions were based on PISA 2000 and PISA 2003. As with the former editions, the current one has received financial support from the Nordic Council of Ministers. The publication has been produced by a working group with representatives, appointed by ministries from the Nordic countries including the Faroe Islands. Members of the working group as well as some invited researchers have made contributions to the anthology.