This paper is meant to be a chapter in an eventual book on EU taxation: a chapter which provides preliminary notions required for an understanding of the EU Parents-Subsidiary Directive. Before the parent-subsidiary directive can be studied, it is essential to have notions on international double taxation, the double taxation of dividends and all kinds of efforts to avoid both of these. This note takes this up. All statements are meant as an example and not to be confused with actual tax rates or systems in the countries.