One of the most successful achievements of the ongoing reform of the Roman Catholic liturgy has been the book called the Lectionary.

Before a look at its contents, a few words about its success. The fathers of the Second Vatican Council asked that we Catholics be exposed during the celebration of the liturgy to more texts of Sacred Scripture. The expanded scriptural texts that are proclaimed, Sunday and weekday, feast day and fast day, are a testimony to a massive undertaking on the part of the Church.

The cycles of readings, three for Sundays and two for weekdays, have brought all of us Catholics a deeper love of Sacred Scripture, inspired Bible study programs in parishes, and revived the ancient Lectio Divina process for meditating on the Lord's Word.

This fruit of Vatican II has also contributed, some say more than anything else, to the advance in ecumenical and interreligious relations, also called for by the council. Our Lectionary over the past six decades has become the basis for the reform of, or introduction into, the worship of our separated sisters and brothers. So, if you were to visit a non-Catholic church on a Sunday, you might well hear the exact same Scripture texts you would at your own parish church.

First, the Lectionary itself is quite a slimmed-down version of what's in your sacristy. The Lectionary is simply a compilation of the citations of the texts assigned to each Mass along with any options that may be used. The reason there are citations only is because the Holy Bible from which the readings are selected and proclaimed will be in various languages -- the vernaculars.

Our U.S. Lectionary, currently undergoing a substantial revision process by our bishops, is in four volumes:

I Sundays and Solemnities (some publishers have separate volumes for each Cycle: A, B, C)

II Weekdays Year I, Saints, and Saints commons

III Weekdays Year II, Saints, and Saints commons

IV Ritual, Votive, and Masses for the Dead

The Lectionary for Sunday is organized around a Synoptic Gospel each year: A -- Matthew; B -- Mark; C -- Luke. As with the liturgical year itself, the respective Gospel book begins to be proclaimed on the First Sunday of Advent and is spread across the remainder of the year until the next First Sunday of Advent. The Gospel of John is sprinkled throughout the year in all cycles, especially at Easter and Christmas. John's exquisite Bread of Life discourse is proclaimed in consecutive weeks (weeks 17 through 21) during Year B because Mark, the shortest of the Gospels, cannot fill out all the weeks.

The weekday Lectionary is in a two-year cycle, with selections coming from both Hebrew and New Testament scriptures. These are usually done in sequence, though not all the books and all their verses may be proclaimed.

During the Easter Season, there is a two-year cycle of weekday readings; most are from the Acts of the Apostles. Also, the preference given to the Gospel of John for both the Sunday and Weekday Gospel readings is a mark of the Easter Lectionary. According to the ancient custom of the Church, the Old Testament is not proclaimed from Easter Sunday up to the vigil of Pentecost. This applies to all liturgical celebrations, not just Holy Mass. There are three exceptions: the Dedication of a Church and Altar; and the rare event when the solemnities of the Annunciation of the Lord and St. Joseph are transferred to Easter days if they occur during Holy Week.

The Lectionary does not refer to the first reading as the Old Testament reading, nor the second as the New Testament reading; rather, as the First Reading before the Gospel or the Second or Only Reading before the Gospel; and there are First Readings during the Easter time as well as outside the Easter time.

An overlooked biblical text at every Mass and almost every other liturgy, though one often very dear to us in our prayers, is the Psalms, often labeled "responsorial" because of the way in which they are proclaimed. Those responsible for compiling the Lectionary took care to relate the psalm to the first reading.

Volume IV has readings for the various other celebrations in the Church's year.

You may also encounter selections from Volume IV in other liturgical books. We'll see that in future columns.

For those who want to delve further into the subject, the indomitable Father Paul Turner provides a "biography" of the Lectionary with his book "Words without Alloy -- A Biography of the Lectionary for Mass." In fact, his book reads exactly like a biography.

Also, Catholic-resources.org is a website with seemingly endless information, some incredibly detailed, about the Bible and its uses in the Roman Catholic Church. It comes from Los Angeles-based Jesuit Father Felix Just.