There was another anniversary on 11 September, of an event whose consequences were just as insidious as those of 2001’s calamity.

The Chilean victims were chosen deliberately, however, rather than as random collateral damage.

I’m talking, of course, about the military coup that removed President Salvador Allende from power in Chile in 1973, the 40th anniversary of which was marked by the publication of this book in hardback.

These days, the coup is a touchstone. Some on the right claim that Allende did not have a widespread mandate, he was bankrupting the country and who knew what would happen if communism was allowed to spread through South America?

This book, written by a London-based Colombian academic, demolishes such assertions punctiliously and without polemic.

Firstly: Allende’s mandate was comparable to, but stronger than David Cameron‘s now. It was a coalition government with the important difference that Allende’s partners, the Christian Democrats, were in many respects as reform-minded as his own Popular Unity party.

Note: “reform” here means “drive to egalitarianism”. It was about nationalising, or removing key industries from private hands to public ones.

Second, the effects that Allende’s policies had included the slashing of unemployment and inflation, the redistribution of wealth and the feel-good knock-ons such results produce.

Third: the election was fair, democratic and constitutional. General René Schneider, leader of the armed forces, was a sworn constitutionalist, pointing out, when the question arose earlier, that any military assault on the elected government would be treason.

Which, if you accept such a statement, would make General Augusto Pinochet Ugarte, formerly in charge of the Pisagua concentration camp for leftist political activists, a particularly egregious traitor.

Even if you are familiar with what happened, this is a book you ought to read.

As Guardiola-Rivera is at pains to point out, Chile’s problems started much earlier.

As well as taking a long view of South American politics, the book takes us back to Allende’s teenage years, when he would visit a radicalised cobbler after finishing his studies for the day.

(An unfamiliarity with the nuances of English and possibly a weak editorial hand mean this first chapter is unfortunately called “Outlaws and Political Cobblers“.) The proximate causes of the end of democracy in Chile were the decisions made by Richard Nixon and Henry Kissinger: to assassinate Schneider, to mobilise the vested interests who stood to lose most from nationalisation and to make the country ungovernable.

The whole story is heartbreaking but necessary to read, especially if you are involved in any movement for popular justice and underestimate the power, paranoia and ruthlessness of the vested interests of capital.

(I confess, though, to some surprise that the election result that first brought Allende to power was allowed by these interests at all. You would think that they would have rigged another outcome.)

It is rare for history to appear in such black-and-white terms: Allende was honourable to the end, as his broadcasts urging non-violence from his supporters from the besieged presidential palace attest; whereas the tally of assassinations, kidnappings, and tortures comes from one side only and is disgustingly large.

So where injustice remains, the struggle continues: here is one of its handbooks.

• To order Story of a Death Foretold for £10.39 with free UK p&p call Guardian book service on 0330 333 6846 or go to guardianbookshop.co.uk.