The Rockefellers built their fortune on it, Britain and the US fought Saddam Hussein to deny him control of it, and scientists say we are now being flooded because of the effects of burning it.
Oil is the lifeblood of industrial economies, and the extent of its use is a barometer of both the ingenuity and shortsightedness of man.
The first bore wells were not drilled in 1859 in Pennsylvannia as many suggest, but 11 years earlier here in Azerbaijan, on the western coast of the Caspian Sea. The world's first oil refinery soon followed.
Surface deposits of Caspian crude oil had been used by man for thousands of years - to waterproof clothing, for torches and sealing boats, and from the 12th century for treating skin and gynaecological diseases. Carried in wineskins through present-day Georgia to the Black Sea, it was shipped all around the known world.
By the 1870s wells were being drilled all over this Central Asian country. By 1890 its capital, Baku, was providing 98 per cent of supplies to Imperial Russia and by 1901 it was producing half the world's oil.
But abundance of natural resources can be a dangerous thing for a small country. Azerbaijan, freed from Russian control after the First World War, was seized by the Red Army in 1920 and remained under Soviet control until 1991. Lenin claimed the "proletariat of Baku" had risen up and toppled the Azerbaijani government, but they drew no share of the oil revenues, which went directly to Moscow.
As Stalin and his successors, scarred by the death of 20 million Russians during Hitler's invasion, searched for oilfields far from European borders, Azerbaijan's share of Soviet production fell from 72 per cent in 1940 to a mere 2.5 per cent by 1980.
When the Sviet Union collapsed, Azerbaijan faced economic breakdown, with 2,000 per cent inflation, and a disastrous conflict with Armenia over the disputed region of Nagorno-Karabakh.
But foreign investment, freed of Soviet restrictions, delivered a series of massive deals to explore rich untapped fields below the Caspian. Boom time for Baku once more.
The deals - one of them dubbed the Contract of the Century - are expected to bring in $210 billion for Azerbaijan by 2022.
However, the years of neglect that led to the Soviet industrial implosion have left a deadly mark. A century's worth of oil production has severely contaminated the land outside Baku, creating standing ponds of oil, vast areas of wasteland and a Baku Bay shoreline black with oil residue.
In an effort to keep up with Moscow's quotas during the Soviet era, petrochemical plants, offshore rigs and refineries released hundreds of thousands of tons a year of toxic waste, run-off and oil spills into the atmosphere or into a creek that feeds the Caspian Sea.
The result, according to the US Energy Information Administration, is that the sea around Baku, where these two boys are swimming, has become a virtual dead zone, and Azerbaijan has "witnessed a dramatic rise in still births and miscarriages". New offshore drilling will make the build-up of harmful pollutants even worse.
Weblinks Official energy and environmental statistics, plus country briefs, from the US government: www.eia.doe.gov Background information on Azerbaijani oil history and the Caspian Sea: www.gia.baku-az.com How oil is found: www. encarta.msn.co.uk and search for oil UK pollution campaign: foe.co.ukcampaignsindustry_and_pollutionfactorywatch Photograph by Peter Andrews