The Catholic Church whose leadership will fall to Pope Paul VII's successor is a vast worldwide institution of 600 million members, fraught with a tension that he was deft at managing, and continuing to change.

Paul's skill was that he was able to keep extremists on the right and the left from splitting away from catholicism while at the same time he greatly encouraged missionaries and clergy in Third World countries who were fighting for justice and human rights against their totalitarian governments.

Under his direction, the internationalization of the church's central administration was carried out and church leadership became less autocratic, giving responsibilities to clergy at all levels as well as to the people.

The ecumenism initially advocated by Paul's predecessor, Pope John XXIII, was advanced through Paul's dramatic personal meetings with such spiritual leaders as the Archbishops of Canterbury and the Orthodox Patriarch of Constantinople. And there is a growing enthusiasm for many Catholics to get to know other Christians and Jews in unprecedented dialogues and cooperative endeavors of spiritual reconciliation.

Paul inherited a church just beginning to wean itself from monolithic forms off worship, prayer and dogma. He left a church in which previously unheard of experiments in worship happen with his sanction every day - the ecstatic charismatic movement, dance in liturgy, deaf and other physically handicapped priests leading worship.

However, the modernization of catholicism, which began with the Second Vatican Council initiated by Pope John and continued by Pope Paul, sent many priests and nuns away, seeking either stricter religious practice that they were able to find in their ever-changing church or the life of the laity - single or married.Many left because of an open breach with catholicism.

Earlier this year, the Vatican reported that resignations from the priesthood total between 2,000 and 5,000 annually. The problem is even more serious among nuns. The Vatican said about 10,000 nuns a year of the one million worldwide left convents between 1973 and 1975.

The liberalization of Catholic worship and doctrine, which provided for more flexibility in faith and practice, also placed a large majority of Catholics, particularly in America, at odds with their church on various key issues, including its bans on divorce and contraception.

Nevertheless, many of them remained active in a Catholic church which has become more tolerant to its dissenters.

Yet this year the U.S. Catholic Conference reported that church rolls were growing - up 500,000 to more than 50 million.

"The church has never been better off, because it is geared to a life of the spirit and taking care of the man on the street," said the Rev. Francis X. Murphy, rector of Holy Redeemer College here.

Worldwide, the institution of catholicism has become a more vigorous political force, both lobbying in legislatures for resolutions to eradicate hunger, poverty and disease and standing up against totalitarian regimes.

Pope Paul's encyclical "Progressio Populorum" - "On the Development of Peoples" - became a textbook for liberation from oppression in all spheres of human interest. He also the gospeletpuPopETAOINSHRDLUN said that violence is not in keeping with the gospel.