Every significant decision affecting China's 1.3bn people is first discussed and approved by a handful of men who sit on the party's political bureau (politburo), the nexus of all power in China.
The 24-member Politburo is elected by the party's central committee. But real power lies with its nine-member standing committee, which works as a kind of inner cabinet and groups together the country's most influential leaders.
How the standing committee operates is secret and unclear.
But its meetings are thought to be regular and frequent, often characterised by blunt speaking and disagreement.
Senior leaders speak first and then sum up, giving their views extra weight. The emphasis is always on reaching a consensus, but if no consensus is reached, the majority holds sway.
Once a decision has been made, all members are bound by it. Although policy disagreements and factional fighting are widely believed to take place in private, it is extremely rare for these to break into the public domain.
When they do – as happened in 1989 when the leadership battled over how to deal with the Tiananmen protests – it is a sign of all-out power struggle.
New politburo members are chosen only after rigorous discussion and investigation of their backgrounds, experience and views.
To reach the top, people need a strong record of achievement working for the party, to have the right patrons, to have dodged controversy, and to have avoided making powerful enemies.
Members of the standing committee also share out the posts of party general secretary, premier, chairman of the National People's Congress, and head of the Central Discipline Inspection Commission.
The full politburo tends to include party secretaries from big municipalities like Beijing and Shanghai, and from important provinces like Guangdong.
Recently, the wealth generated by China's economic reforms has led some analysts to suggest the power of the centre is waning.
It is pointed out that party secretaries of large provinces like Sichuan and Guangdong are in charge of populations bigger than most European countries, and that their tax revenues are vital to Beijing.
But it is difficult to see them getting free from Beijing's political grip so long as the country's political system remains so closed.