Poland's Catholic Church has published a major two-volume work on political science and philosophy by Pope John Paul II, written when he was a young priest and university lecturer in the early 1950s, which is widely expected to affect interpretations of his teaching and require a revision of existing biographies.

Katolicka Etyka Spoleczna (The Catholic Social Ethic), now released as a 573-page work by the John Paul II Institute at the Catholic University of Lublin, was prepared by the then Fr Karol Wojtyla for his students when most works on Catholic social teaching had been suppressed by Poland's communist rulers.

It includes extensive material on Marxism, socialism and communism, and includes concepts such as "solidarity" and "moral victory" which were later used by the Catholic Church under his guidance in the struggle against communist injustices.

It includes sections on "Class struggle and the commandment of love", "The issue of revolution", and "The objective superiority of the communist ideal", and discusses Catholic justifications for revolutionary violence and aspects of economic and historical determinism.

An accompanying commentary said the two-volume work should be seen in the "specific historical context" of communist rule, and was intended by the future Pope for his own use, rather than for general publication.

However, it added that Katolicka Etyka Spoleczna also showed a consistency in the Pope's life-long inner views on capitalism, liberation theology and other "key social questions", and would provide "an important source text" for "settling debates" on aspects of John Paul II's teaching.

The text also offered a "hermeneutic key", the commentary said, for understanding the Polish Pope's social encyclicals, Laborem Exercens (1981), Solicitudo Rei Socialis (1987) and Centesimus Annus (1991).

"As Pope, he clearly formulated the same methodological directive in the encyclical Fides et Ratio where - referring to Pius XII's Humani Generis - he stressed the necessity to know even the doctrines in which the Church's teaching was expressly rejected, since 'even in these false theories, some truth is found'", the commentary quoted Fr Wojtyla as saying.

"He understood the social and moral motives, as well as the critical diagnosis of the capitalist system, which inspired the Marxists' commitment to the cause of working people... Like the communist ones, the solutions to social issues offered by liberalism proved, in Wojtyla's view, to be a cure worse than the disease".

The commentary said there was no evidence for claims by the US author, George Weigel, in his monumental 1999 biography, Witness to Hope, that Wojtyla should not be regarded as the work's author, since he had used course outlines from an older colleague, Professor Jan Piwowarczyk (1889-1959).

The Catholic University's rector, Fr Antoni Debinski, told Polish Radio on Monday the indexing and cross-referencing of Katolicka Etyka Spoleczna had needed a "whole team of editors and researchers", adding that its final publication should be seen as an "exceptional event".