Mass Part 1: What is mass?

I've had several folks ask me about Mass... so here is a brief overview of what it is, why we celebrate it, and what books or instruction we use. Instead of pulling up documents that are heavily laden with terms that most nonCatholics won't understand, I used Wikipedia:

Mass is the term used to describe celebration of the Eucharist in the Western liturgical rites of the Roman Catholic Church. The term is derived from the late-Latin word missa (dismissal), a word used in the concluding formula of Mass in Latin: "Ite, missa est" ("Go, it is the dismissal") For the celebration of the Eucharist in Eastern Churches, including those in full communion with the Holy See of Rome, other terms, such as the Divine Liturgy, the Holy Qurbana, and the Badarak are normally used.

The Council of Trent reaffirmed traditional Christian teaching that the Mass is the same Sacrifice of Calvary offered in an unbloody manner: "The victim is one and the same: the same now offers through the ministry of priests, who then offered himself on the cross; only the manner of offering is different. And since in this divine sacrifice which is celebrated in the Mass, the same Christ who offered himself once in a bloody manner on the altar of the cross is contained and offered in an unbloody manner... this sacrifice is truly propitiatory" (Doctrina de ss. Missae sacrificio, c. 2, quoted in Catechism of the Catholic Church, 1367). The Council declared that Jesus instituted the Mass at his Last Supper: "He offered up to God the Father His own body and blood under the species of bread and wine; and, under the symbols of those same things, He delivered (His own body and blood) to be received by His apostles, whom He then constituted priests of the New Testament; and by those words, Do this in commemoration of me, He commanded them and their successors in the priesthood, to offer (them); even as the Catholic Church has always understood and taught."

The Roman Catholic Church sees the Mass as the most perfect way it has to offer latria (adoration) to God. It is also Catholic belief that in objective reality, not merely symbolically, the wheaten bread and grape wine are converted into Christ's body and blood, a conversion referred to as transubstantiation, so that the whole Christ, body and blood, soul and divinity, is truly, really, and substantially contained in the sacrament of the Eucharist

TEXTS USED DURING MASS:
The Roman Missal contains the prayers and rubrics of the Mass. Before the 1970 revision of the Roman rite of Mass (see Mass of Paul VI), the Missal contained not only the prayers of the Mass itself, with the prayers for each day of the calendar, but also the scriptural readings for each day.

In the United States and Canada, the English translation of the Roman Missal is at present called the Sacramentary.

The Lectionary presents passages from the Bible arranged in the order for reading at each day's Mass. Compared with the scripture readings in the pre-1970 Missal, the modern Lectionary contains a much wider variety of passages.
A Book of the Gospels called the Evangelary is recommended for the reading from the Gospels, but the Lectionary may be used in its place.

Time of Celebration of Mass
Before the liturgical reforms of Pope Pius XII from 1951 to 1955, it was forbidden, except for Midnight Mass on Christmas night, to begin Mass more than one hour before dawn or more than one hour after midday. In the Apostolic Constitution Christus Dominus (1953) and the Motu Propio Sacram Communionem (1957) Pius XII permitted the celebration of Mass at other times. There are no longer any time limits. Furthermore, since the Second Vatican Council, the time for fulfilling the obligation to attend Mass on Sunday or a Holy Day of Obligation now begins on the evening of the day before (in theory, after First Vespers), and most parish churches do celebrate the Sunday Mass also on Saturday evening. By long tradition and liturgical law, Mass is not celebrated at any time on Good Friday (but Holy Communion is, since the reform of Pope Pius XII, distributed to those participating in the Celebration of the Passion of the Lord with hosts consecrated at the evening Mass of the Lord's Supper on Holy Thursday) or on Holy Saturday before the beginning of the Easter Vigil.

In addition, before Pope Pius XII, the Eucharistic Fast (to which the priest too was bound) extended from the midnight before Mass was celebrated, thus making it impractical to celebrate Mass much after noon anyway. Pius XII reduced the fast from food and alcohol to three hours, reduced the fast from non-alcoholic beverages to one hour, and excluded water from fast regulations. Pope Paul VI in 1964 reduced the fast to one hour before receiving communion.

Priests and bishops are required, from the time of their ordination as deacons, to celebrate the Liturgy of the Hours daily, but are not obliged to celebrate Mass daily. "Apart from those cases in which the law allows him to celebrate or concelebrate the Eucharist a number of times on the same day, a priest may not celebrate more than once a day" (canon 905 of the Code of Canon Law), and "a priest may not celebrate the Eucharistic Sacrifice without the participation of at least one of the faithful, unless there is a good and reasonable cause for doing so" (canon 906).

Priests may be required by their posts to celebrate Mass daily, or at least on Sundays, for the faithful in their pastoral care. The bishop of a diocese and the pastor of a parish are required to celebrate or arrange for another priest to celebrate, on every Sunday or Holy Day of Obligation, a Mass "pro populo" - that is, for the faithful entrusted to his care.

For Latin-Rite priests, there are a few general exceptions to the limitation to celebrate only one Mass a day (General Instruction of the Roman Missal, 204). By very ancient tradition, they may celebrate Mass three times at Christmas (the Midnight Mass or "Shepherd's Mass", the Dawn Mass and the Day Mass, each of which has its own readings and chants).

On All Souls' Day they may also, on the basis of a privilege to all priests by Pope Benedict XV in August 1915, celebrate Mass three times, but not immediately one after the other; only one of the three Masses may be for the personal intentions of the priest, while the other two Masses must be applied, one for all the faithful departed, the other for the intentions of the Pope. A priest who has concelebrated the Chrism Mass, which may be held on the morning of Holy Thursday, may also celebrate or concelebrate the Mass of the Lord's Supper that evening. A priest may celebrate or concelebrate both the Mass of the Easter Vigil and Mass during Easter day (the Easter Vigil "should not begin before nightfall; it should end before daybreak on Sunday"; and may therefore take place at midnight or in the early hours of Easter morning). Finally, a priest who has concelebrated Mass at a meeting of priests or during a pastoral visitation by a bishop or a bishop's delegate, may celebrate a second Mass for the benefit of the laity.

In addition to these general permissions, the Local Ordinary may, for a good reason, permit priests to celebrate twice (they are then said to "binate," and the act is "bination") on weekdays, and three times ("trinate," and "trination") on Sundays and Holy Days (canon 905 §2). Examples would be: if a parish priest were to need to celebrate the usual, scheduled daily Mass of a parish, and a funeral later in the morning, or three Masses to accommodate all of the parishioners in a very populous parish on Sundays. In particularly difficult circumstances, the Pope can grant the diocesan bishop permission to give his priests faculties to trinate on weekdays and quadrinate on Sundays.
In many countries, the bishop's power to permit bination and trination is widely availed of, so that it is common for priests assigned to parish ministry to celebrate at least two Masses on any given Sunday, and two Masses on several other days of the week. Permission for quadrination has been obtained in order to cope with large numbers of Catholics either in mission lands or where the ranks of priests are diminishing.

Special Masses

Nuptial Mass and other Ritual Masses
A Nuptial Mass is simply a Mass within which the sacrament of Holy Matrimony is celebrated. Other sacraments too are celebrated within Mass. This is necessarily so for the sacrament of Orders, and is normal, though not obligatory, for the sacrament of Confirmation, as well as that of Holy Matrimony. Unless the date chosen is that of a major liturgical feast, the prayers are taken from the section of the Roman Missal headed "Ritual Masses". This section has special texts for the celebration within Mass of Baptism, Confirmation, Anointing of the Sick, Orders, and Holy Matrimony, leaving Confession (Penance or Reconciliation) as the only sacrament not celebrated within a celebration of the Eucharist. There are also texts for celebrating within Mass, Religious Profession, the Dedication of a Church, and several other rites.

If one of a couple being married in a Catholic church is not a Catholic, the rite of Holy Matrimony outside Mass is to be followed. However, if the non-Catholic has been baptized in the name of all three persons of the Trinity (and not only in the name of, say, Jesus, as is the baptismal practice in some branches of Christianity), then, in exceptional cases and provided the bishop of the diocese gives permission, it may be considered suitable to celebrate the marriage within a Mass, except that, according to the general law, Communion is not given to the non-Catholic (Rite of Marriage, 8).