Illuminating

A discussion at another blog questioned the validity of Pope John Paul II's addition of the 'Luminous Mysteries' to the devotion of the Rosary. I'll break it down into two issues: Why the Luminous Mysteries, and Why by the Pope adding them.

a link to JPII's document Rosarium Virginis Mariae for starters.

According to legend, in the early 13th Century, St. Dominic was instructed by Our Lady to institute the devotion of the Rosary, as a defense against heresy and sin. The meditations on the Mysteries, Joyful, Sorrowful, and Glorious, were codified by Pope Pius V in the late 16th Century. Pope John Paul II, in 2002, added the Luminous Mysteries to these meditations. The Luminous Mysteries are: The Baptism in the Jordan, The Wedding at Cana, The Proclamation of the Kingdom, The Transfiguration, and The Institution of the Eucharist.
To answer the Why of the addition, it is another way to contemplate the Glory of Jesus through key events that define our christology as Catholics.

The Baptism in the Jordan: Jesus was already holy before His Baptism, as proclaimed by John the Baptist upon meeting Jesus on the bank of the river. It's important, as it dispells the Adoptionist myth of Jesus 'becoming' Christ upon His Baptism.

The Wedding at Cana: Not only Jesus' first public miracle, but also shows the intercessory role of Mary with Jesus.

The Proclamation of the Kingdom: Jesus is the King, and therefore it was good news to Israel that the Kingdom of God was really as hand.

The Transfiguration: As a spiritual consolation or strengthening to His closest disciples, Jesus allows them to see Him as He really is.

The Institution of the Eucharist: The Eucharist as Source and Summit is meaningless without this event, and so it is right to be a frequent topic for meditation.

The question as to 'Why the Pope adding them' is simple: The Pope, as Vicar of Christ, has every obligation to safeguard the Faith and promote the spiritual growth of Catholic Christians. As the successor of Peter, he is also gifted with the Holy Spirit, which proceeds from the Father and the Son, whose testimony gives glory to Jesus. These added mysteries invite meditation on key events in the Gospel, to glorify Jesus, and so are beneficial to our spiritual growth.
Some may dismiss these additional Mysteries as an unwarranted innovation, but they do so at their own peril, for in that dismissal lies a contempt for the Pope and, by extension, the Chair of Peter. The Church has seen many trivializations of prayer and liturgy, by liberal elements, in the years since the Second Vatican Council, and many blame the Council itself for these lapses. But this dissatisfaction does not excuse contempt for, and even defiance of, the successor of Peter in the name of 'Tradition'. The Church teaches that the successors of the Apostles were guided by the Holy Spirit, and that the Holy Spirit is the guidance to the Church. Either you believe it, or you despair of it.