Since 1975, the heads of state or government of the major industrial democracies have been meeting annually to deal with the major economic and political issues facing their domestic societies and the international community as a whole. The six countries at the first summit, held at Rambouillet, France, in November 1975, were France, the United States, Britain, Germany, Japan and Italy (sometimes referred to as the G-6). They were joined by Canada at the San Juan Summit of 1976 in Puerto Rico, and by the European Community at the London Summit of 1977. From then on, membership in the Group of Seven, or G-7, was fixed, although 15 developing countries' leaders met with the G-7 leaders on the eve of the 1989 Paris Summit, and the USSR and then Russia participated in a post-summit dialogue with the G-7 since 1991. Starting with the 1994 Naples Summit, the G-7 met with Russia at each summit (referred to as the P8 or Political Eight). The Denver Summit of the Eight was a milestone, marking full Russian participation in all but financial and certain economic discussions; and the 1998 Birmingham Summit saw full Russian participation, giving birth to the Group of Eight, or G-8 (although the G-7 continued to function along side the formal summits). At the Kananaskis Summit in Canada in 2002, it was announced that Russia would host the G-8 Summit in 2006, thus completing its process of becoming a full member. After the invasion of Crimea in 2014, Russia has no longer joined the Summits. In 2017 the summit took place in Italy (Taormina), in 2018 will be in Canada (Charlevoix).
Further information on summits, documents and analyses are available here