The term Scandinavia has historically referred to the kingdoms of Denmark, Norway and Sweden, but you will also find countries with cultural and historical similarities, such as Finland, Greenland, and Iceland included. For a stamp collector, colonies once ruled by these countries, such as the Danish West Indies, may also be considered Scandinavian.
If you are a collector who focuses on any of these countries, I heartily recommend joining the Scandinavian Collector's Club (SCC). This organization was founded in 1935 and has a rich history of educating collectors in all things Scandinavian.
While there are many benefits to membership in the SCC, there are two that are very popular with members. The first is the award-winning publication THE POSTHORN, published in 1943 with excellent information about Scandinavian collecting.
The second benefit of the SCC is its fantastic stamp circuits. I believe I have purchased stamps for my collection from every circuit that arrives in my mail. The deals found in the circuit books are excellent; one gets the feeling that some of the sellers purposely sell their stamps at a very fair price just to help their fellow collectors expand their collections.
Membership in the SCC costs only $25 per year and it is money well spent. More information can be found at http://www.scc-online.org.