Zero Zero Zero. By Roberto Saviano. Translated by Virginia Jewiss. Penguin Press; 416 pages; $29.95. Allen Lane; £20.

ROBERTO SAVIANO’S first book, “Gomorrah”, put him in grave danger. An exposé of the Neapolitan mafia, the Camorra, it sold over 10m copies. But it also struck a nerve with its subject, and death threats soon followed. Mr Saviano, an Italian journalist, now moves between safe houses under 24-hour police protection. He dedicates his new book “to all my Carabinieri bodyguards. To the fifty-one thousand hours we’ve spent together and to those still ahead.”

His movement may have been curtailed, but not his anger or ambition. His latest book, “Zero Zero Zero”, is an exploration of the global cocaine trade, from the foothills of the Andes to the nightclubs of Europe. It is a well-trodden trail, but the book provides a useful overview of the industry, explaining the incongruous mix of co-operation and cruelty in each link of the supply chain.

Cocaine-trafficking is risky but enormously profitable. As Mr Saviano points out, a kilo of the drug costing $1,500 in Colombia fetches $12,000-$16,000 in Mexico and $77,000 if it makes it to Britain. According to the accountant of Colombia’s Medellín drug mob, the group was trafficking 15 tonnes of cocaine into America every day in the 1980s. Thirty years later, the figures are still staggering. In Italy the Calabrian ’Ndrangheta has now overtaken the Sicilian Cosa Nostra as the country’s most powerful mafia group. It turns over an estimated €53 billion ($59 billion) a year, almost half of which comes from drug-trafficking.

The book does a fine job of tracing the international co-operation required to get the drug to market. In Colombia, producers struck distribution deals with their Mexican counterparts after American authorities grew adept at intercepting their cocaine shipments. In exchange for a large chunk of the profits, the Mexicans agreed to move the drugs across the border. Alliances have also been formed with groups from further away. The Russian mafia supplies Latin American gangs with Soviet-era weapons. West African government officials store drug shipments off the coast.

In an often grisly series of passages, Mr Saviano details some of the murderous national rivalries that occasionally make the front pages. In 2006 Mexico was plunged into violence when the president, Felipe Calderón, declared war on the drug gangs by sending 6,500 troops to the troubled state of Michoacán. Over 47,000 people were killed by violence associated with organised crime between 2006 and 2011, says the government. In the first six years of the drug war 31 Mexican mayors were killed, 13 of them in 2010 alone.

The most vivid sections are those describing the industry’s countless victims: the young man from Guinea-Bissau who spends a flight to Lisbon praying that the 60 capsules of cocaine in his stomach will not burst; the Colombian beauty queen whose husband has disappeared; the American undercover agent who is tortured to death when his cover is blown, his body dumped beside a Mexican road.

Structurally, the book is a bit of a mess. Lacking a coherent narrative, it is more a collection of articles, lurching from one topic to another. The effect is often disorientating and sometimes offputting. A chapter on Los Zetas, a ferocious group of Mexican traffickers composed of former soldiers, is followed, inexplicably, by a syrupy poem about cocaine. Better editing would have made for an easier read.

Despite its shortcomings, the book lands a resounding thump to the solar plexus. Taken as a whole, it is an angry rebuke to all those—traffickers and politicians alike—who perpetuate the violence. “I want to scream this loud enough so that people will know,” writes Mr Saviano. His rage, both at his own predicament and that of other victims, is palpable. “As terrible as it may seem, total legalisation may be the only answer,” he concludes. By reminding readers of the senseless suffering wrought by the cocaine trade, this book makes a powerful case for a new approach.