G8: the main players
Q David Cameron (Britain)
British prime minister since 2010. As leader of the rotating G8 presidency, Mr Cameron is chairing the summit at Lough Erne. Cracking down on international tax evasion, EU-US trade talks and achieving a Syrian peace conference are all key objectives.
Q Barack Obama (United States)
US president since 2008, Mr Obama hosted the previous G8 summit in 2012. He is due to hold a bilateral meeting with Vladimir Putin on the sidelines and will also kick-start a Syria session at the request of host Britain.
Q Stephen Harper (Canada) Prime minister since 2006, Mr Harper is now in his third term. The G8 meeting comes as Canada is negotiating a free-trade agreement with the European Union, although his officials have played down expectations a deal will be announced during this trip.
Q Francois hollande (France)
Elected president in 2012, his government is facing a troubled time at home in the face of massive public spending, growing unemployment, and negative economic growth. He is just back from France's first state visit to Japan in 17 years, where he was generous in his praise of the policies being pursued by Japanese prime minister Shinzo Abe. He said Japan and Europe needed to co-operate to forge an economic partnership that would be good for both.
Q angela merkel (Germany)
Chancellor since 2005, Ms Merkel is preparing for parliamentary elections due in September. She is expected to focus her attention on policies for fighting tax evasion.
Q enrico letta (Italy)
Prime minister since April, Mr Letta is leading a grand coalition with the main conservative and centrist parties. Not expected to be a key mover or shaker.
Q shinzo abe (Japan)
Prime minister since December 2012, he previously served in 2006-2007. Mr Abe is the chairman of the conservative Liberal Democratic Party.
Q vladimir putin (Russia)
Longest-serving leader of G8 countries. He has been president of Russia since May 2012, but served two previous terms from 1999 to 2008. Mr Putin will chair the G8 summit at Sochi in 2014. Refused to attend the last G8 summit.
Q the european union
Jose Manuel Barroso, Herman van Rompuy and Enda Kenny will all attend.