Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The official rules of the Eurovision Song Contest are long, technical, and ever-changing. Many of the rules cover technical aspects of the television broadcast itself. However, a few of the more important rules affecting the conduct and outcome of the Contest follow. At the first Contest, each country was allowed to submit two songs each with a maximum duration of three minutes. Nowadays, it is still required that each song not exceed three minutes in length, although many artists record the song in a longer version, simply performing a shorter version at the Contest. The number of participating countries has grown throughout the Contest''s history, and since 1993 the rules have been changed several times to both limit the number of finalists and to allow for participation by former Soviet and Yugoslav republics, Warsaw Pact nations and others. The entering song is also not allowed to be a cover version, and is not allowed to sample another artist''s work. All songs must be completely original in terms of songwriting and instrumentation, and may not have been released publicly before 1 October of the year preceding.