The extractive industries – the development and exploitation of oil, gas, and mining resources — are a critical area for investigative journalists, particularly in developing countries. Revenues from natural resource extraction may contribute heavily to GDP and even make up the bulk of government revenue. They impact on the economy, political power, and social well-being. The companies in the extractive sector are large and influential. How they win the contracts and make their profits, and how governments spend their share of often vast sums, all require scrutiny. Here are tips on how to find the data, decipher the jargon, follow the money, and ferret out corrupt practices.