The issue of Light Pollution was a major concern of the International Astronomical Union; during the IAU General Assembly in the city of Rio de Janeiro in 2009. A resolution was unanimously adopted (Resolution B5) to support the need to preserve the night sky and the right to see stars. With the increasing use of artificial light at night posing a growing threat to the visibility of the night sky, this Special Session at the XXVIIIth General Assembly highlighted technical aspects of astronomical site protection and the educational aspects of increasing global awareness on issues concerning light pollution.