The document summarizes the history and events leading up to the UK's decision to leave the European Union (Brexit): - The EU was formed in 1957 and gradually integrated economically and politically, adopting a common currency among other policies. - The UK joined the EU in 1973 but a referendum in 1975 saw most voters in favor of remaining. Euroskeptic parties gained popularity over time. - A 2016 referendum was called where 52% voted to leave the EU, driven partly by concerns over sovereignty, immigration, and fees paid to the EU. - The Brexit vote had significant economic and political consequences, and formally leaving the EU will involve a complex withdrawal process as outlined in the EU's Lisbon