The four government ministries that control the world of Big Brother are introduced in Part 1, Chapter 4 of the book 1984 by George Orwell. The chapter is titled "The Ministry of Truth" and it explains that there are four ministries in Oceania, each with a specific role in maintaining the regime's control over the population.
The four ministries are:
1. The Ministry of Truth - responsible for propaganda, news, entertainment, education, and the rewriting of historical documents to fit the party's ideology.
2. The Ministry of Peace - responsible for maintaining Oceania's military forces and waging war against the other two superstates, and Eurasia.
3. The Ministry of Love - responsible for law and order, including the Thought Police, who monitor and punish any dissent against the party.
4. The Ministry of Plenty - responsible for economic affairs, including the production and distribution of goods and the control of rationing.
These ministries work together to maintain the totalitarian control of the ruling party over the citizens of Oceania.