A population of about 5 million at the northern corner of Europe is unlikely to arouse the attention of the human genetics community, unless it offers something useful for others to learn. A combination of coincidences has finally made this population one that, out of proportion for its size, has by example shaped research in human disease genetics. This chapter summarizes advances made in medical genetics that are based on research facilitated by Finland's population structure. The annotation of the human genome for its polymorphism and involvement in disease is not over; it is, therefore, of interest to assess whether genetic studies in populations such as the Finnish might help in the remaining tasks.