Wherever governments fail and lawlessness prevails, a new sector is blossoming: Private military firms, known as PMFs, have been expanding tremendously since the 1990s.

Take Sierra Leone in 1995, for example. A civil war has been raging for the past four years. The rich diamond mines, this otherwise dirt-poor nation's lifeline, have long since been under the control of rebel forces. The Revolutionary United Front (RUF) has thrown the country into anarchy. Gangs of rebels raid and pillage throughout the countryside, setting entire villages on fire at night. Uninhibited child soldiers lead regiments of terror, and their trademark is hacking off limbs with machetes.

These bands of rebel soldiers are now 20 kilometers from the capital, Freetown, to which tens of thousands have fled, and it appears that a final massacre is only days away. But then, like the white knights of mythology, a secret force flies into Freetown. It uses precision aerial bombing to attack the rebels. The first wave is followed by helicopter gunships and tanks.

Within less than two weeks, the professionals have recaptured the mines and overrun the RUF's strongholds. Only 160 men - with no national emblems, flags or national colors - have devastatingly defeated an enemy that vastly outnumbered them. The men were hired by the beleaguered government. They were recruited by Executive Outcomes (EO), a South African mercenary organization, and the cost of the mission was somewhere between 35 and 60 million dollars.

Mercenary companies provide assistance with the efficiency of major corporations - and do so for almost anyone willing to pay for their services.

A short time later, EO offered the UN its services to avert the genocide that threatened to engulf Rwanda, where thousands of Tutsi were being pursued by Hutu fighters. The EO strategists presented detailed plans to separate the two ethnic groups. A safe corridor was to created for refugees, but UN Secretary General Kofi Annan, trusting in the UN's ability to deal with the crisis, rejected the offer: "The world is probably not prepared to treat peacekeeping as a private mission."

Today, Peter W. Singer, author of an extensive study on PMFs, believes that EO "could have saved hundreds of thousands of people." Private contractors are usually deployed far more quickly than nationally or even internationally organized forces.

Nevertheless, this involvement on the part of private crisis managers, based as it is on business interests and not on any moral convictions, is controversial. The fact is that Africa, once overrun by mercenaries under the command of the likes of a "Congo Jones," is one of their most lucrative deployment regions. Operating as efficiently as major corporations, PMFs provide assistance, including armed assistance, to just about anyone willing to pay their price.

80 such companies were involved in the Angolan civil war alone between 1975 and 2003, companies staffed with decommissioned gladiators from all over the world: French Foreign Legionnaires, South African paratroopers, Ukrainian pilots, Nepalese Ghurkas.

Executive Outcomes entered the conflict in 1993. EO pilots flew missions against the Unita rebels. A competitor, International Defense and Security (Idas), concentrated on protecting the lucrative diamond mines. Airscan, an American firm specializing in private air reconnaissance, sent spy planes, while two Anglo-Saxon companies, Ronco and DSL, specialized in clearing minefields.

Unita also recruited foreign training personnel and tank and artillery specialists. In return for assurances of oil concessions, Ukrainian companies even provided a small fleet of MiG-27 and MiG-21 fighter jets, as well as Mi-24 helicopter gunships, pilots included.

In the Congo, formerly known as Zaire, all parties to the civil war hired private military contractors. However, PMF Geolink, a French firm, was unable to avert dictator Sese Mobutu's defeat at the hands of his rival, Laurent Kabila. Kabila, in turn, relied on EO specialists when he ran into trouble. His opponents, former Mobutu supporters as well as the neighboring countries of Rwanda and Uganda, hired a company called Stabilco and another South African firm. Avient, a US-based team, conducted air attacks for Zimbabwe, another participant in the great central African conflict.

PMFs are a global billion-dollar business. Guarding oil fields and mines is especially lucrative, sometimes paying twice as much as other work. Their clients occasionally grant mining rights to companies closely affiliated with the private military contractors. "In fact, the private contractors are really heating up the conflict in central Africa," says French defense minister Michèle Alliot-Marie. Last year, France imposed criminal penalties on all kinds of mercenaries.

Great Britain also intends to gain control over these business-minded former soldiers and intelligence agents. However, when the government in Sierra Leone was deposed in 1997, a London-based company, Sandline International, helped President Kabbah regain power - with the British government's secret blessing.

PMFs have also been unusually successful in the Balkans. For three years, Belgrade's forces had been busy decimating their Bosnian and Croatian opponents.

These part-time soldiers, poorly equipped and even more poorly trained, were no match for the Serbs. But the tables turned in the spring of 1995. In a lightning operation previously unheard of in this conflict, Croatian troops recaptured the town of Krajina, which had been occupied by the Serbs. Instead of an overtaxed militia, well-armed and trained professionals were responsible for "Operation Storm."

This was certainly no accident. In spite of the UN embargo, experts from a Washington-based firm, MPRI, had taken on the task of training the Croatian forces, with the US government's approval. The company, today managed by former US military chief of staff Carl Vuono, one of Secretary of State Colin Powell's closest friends, officially denied any involvement. Soon afterwards, however, in Dayton, the Bosnian Muslims made it abundantly clear just how decisive their involvement was for the outcome of the war. They were only willing to sign a truce on the condition that they too would receive MPRI assistance.

Nowadays, virtually all US overseas military bases are constructed and, at least in the Balkans, guarded by PMFs. In Afghanistan, bodyguards from a company called DynCorp protect President Hamid Karzai, who is currently in great danger. On the other side of the world, in Columbia, the US has significantly privatized its war against drug lords and guerillas. Almost half of the 370 million dollars earmarked for fighting the drug trade under "Plan Columbia" was paid to PMFs. A total of 17 firms are under contract for 23 projects.

In most cases, the people who service the hi-tech equipment and helicopters, accompany crop dusters on missions to spray coca plantations, or reconnoiter the jungle are war veterans, former CIA agents and retired air force pilots. Washington has also hired former members of the Peruvian military and Central American specialists to fight the guerillas.

Just last September, a spy plane was shot down over rebel territory. It was an OV-10 Bronco, a type of aircraft used for air reconnaissance back in the Vietnam War, and its mission was to look for coca fields on behalf of DynCorp.

The company, headquartered in Reston, Virginia, is the largest military contractor in Columbia, and has been in the country since 1997. It earns about 80 million dollars a year for providing logistical assistance to wipe out coca plantations and for training Colombian pilots on US equipment. DynCorp personnel are also involved in missions to rescue kidnapped Americans.