(Copied from http://catholicstraightanswers.com/what-is-a-novena/)
Succinctly, a novena is a nine day period of private or public prayer to obtain special graces, to implore special favors, or make special petitions. (Novena is derived from the Latin novem, meaning nine.) As the definition suggests, the novena has always had more of a sense of urgency and neediness.
The origin of the novena in our Church’s spiritual treasury is hard to pinpoint. The Old Testament does not indicate any nine-days celebration among the Jewish people. On the other hand, in the New Testament at the Ascension scene, our Lord gives the apostles the Great Commission, and then tells them to return to Jerusalem and to await the coming of the Holy Spirit. Acts of the Apostles recounts, “After that they returned to Jerusalem from the mount called Olivet near Jerusalem– a mere Sabbath’s journey away. Together they devoted themselves to constant prayer” (Acts 1:12,14). Nine days later, the Holy Spirit descended upon the Apostles at Pentecost. Perhaps, this “nine-day period of prayer” of the apostles is the basis for the novena.
Whatever the exact origins may be, the early Christians did have a nine-day mourning period upon the death of a loved one. Eventually, a novena of Masses for the repose of the soul was offered. To this day, there is the novendialia or Pope’s Novena, observed upon the death of the Holy Father. Similarly, many parishes have novenas beginning on All Souls Day to pray for the faithful departed.
In the Middle Ages, particularly in Spain and France, novenas of prayers were offered nine days before Christmas, signifying the 9 months our Lord spent in the womb of our blessed Mother. These special novenas helped the faithful prepare for the festive, yet solemn, celebration of the birth of our Lord. Eventually, various novenas were composed to help the faithful prepare for a special feast or to invoke the aid of a saint for a particular reason. Some of the popular novenas still widely used in our Church include those of the Miraculous Medal, Sacred Heart of Jesus, St. Joseph, and St. Jude, to name a few.
It is difficult to say why we do not find novenas as much a part of public worship now as before Vatican II. I remember asking this question to an elderly priest, who basically said that he remembered people who would skip Mass yet attend the weekly novena. As Catholics, the primary focus of our spirituality and public worship should be the Holy Eucharist and the Mass. With the advent of the liturgical renewal and the increased participation of the congregation at Mass, perhaps this is why novenas fell by the wayside.
Also, some people I think have hurt the cause of novenas because of superstition. In every parish I have been assigned, I have found copies of a St. Jude novena which basically states that if a person goes to Church for nine days and leaves a copy of the novena to St. Jude, then the prayer will be granted– sort of like a spiritual chain letter. This is dispensing machine Catholicism: just as a person puts the coin in the vending machine and presses the button to get the desired soda, here a person says the prayers, goes to church, and is supposedly guaranteed that the request will be granted. So much for God’s will. What is really sad these days is that the person simply Xeroxes the letter; one would think they could at least hand-write it. Worse yet, I usually have to pick up these letters which are left all over the Church.
Nevertheless, novenas still hold a legitimate place in our Catholic spirituality. The Enchiridion of Indulgences notes, “A partial indulgence is granted to the faithful, who devoutly take part in the pious exercise of a public novena before the feast of Christmas or Pentecost or the Immaculate Conception of the Blessed Virgin Mary” (#34). Here the Church is again emphasizing that the novena is a pious, spiritual exercise to bolster the faith of the individual, and that the individual should be truly devout, always remembering the goodness of the Lord who answers all of our prayers according to His divine will.