In 1977, the Colombian journal Ideología y Sociedad devoted twenty-eight pages of its twenty-first issue to an attack on Ernest Mandel's The Leninist Theory of Organisation. The author was Nahuel Moreno, leader of the Argentinian Trotskyist current that bore his name. The journal belonged to the Bloque Socialista, a Colombian organisation then seeking adhesion to the Fourth International. The attack was published without the texts it was attacking.

Mandel replied in Spanish, the language of the polemic, for the same readers Moreno had addressed. The reply has, until now, never appeared in English.

It is more than a factional document. Behind the dispute over the category of the 'broad vanguard' and the role of advanced workers, Mandel is defending the 1938 Transitional Programme against a reading that collapses it back into the maximum-and-minimum-programme architecture of classical Social Democracy. What Moreno calls metaphysical scholasticism, Mandel argues, is the characteristic failure mode of a certain kind of Trotskyist orthodoxy: a taxonomy of concepts substituted for the materialist analysis of live social forces.

The questions remain live. How does class consciousness actually develop in a period of decomposed labour organisation? What does the category of the advanced worker mean when the institutional workers' movement has been hollowed out? How do transitional demands function today? Can materialist dialectics survive being reduced to a system of boxes labelled 'base' and 'superstructure'?

This first English edition is presented as a working text rather than a finished scholarly one, with an editor's preface placing the polemic in its moment and explaining its continuing relevance for contemporary movements. Readers working inside broad-party projects, fragments of the Trotskyist tradition reassembling themselves after forty years of dispersal, and current debates over the strategic use of the transitional method will find Mandel's argument transposes with uncomfortable ease.