From the Vatican Information Service:
ST. CATHERINE: SPIRITUAL COUNSELLOR, DOCTOR OF THE CHURCH
VATICAN CITY, 24 NOV 2010 (VIS) - During his general audience, held this morning in the Paul VI Hall in the presence of 7,000 faithful, Benedict XVI focused his catechesis on St. Catherine of Siena (1347-1380), declared a Doctor of the Church by Paul VI and co-patroness of Europe by John Paul II.
At the age of sixteen she became a Dominican Tertiary, dedicating herself to prayer, penance and works of charity, especially towards the sick. "As fame of her sanctity spread", the Pope explained, "she became intensely active in the spiritual counselling of many categories of peoples: nobles, politicians, artists, common people, consecrated persons, ecclesiastics, and even Pope Gregory XI who at that time resided in Avignon and whom Catherine energetically and effectively encouraged to return to Rome. She also travelled widely to promote interior reform of the Church and peace among States". She expounded her doctrine in three works: the "Treatise on Divine Providence", her "Letters" and a collection of "Prayers".
Catherine was also a great mystic. Particularly famous are her visions of her exchanging hearts with Christ, and of the Virgin presenting her the Baby Jesus Who gives her a ring. "The living centre of Catherine's religiosity and of all authentic spirituality", the Holy Father explained, "is Christocentrism. For her, Christ was as a bridegroom with whom she maintained a relationship of intimacy, communion and fidelity. ... Like the saint of Siena, all believers feel the need to conform themselves to the sentiments of Christ's Heart, in order to love God and neighbour as Christ Himself loves. And, indeed, we can all allow our hearts to be transformed and learn to love like Christ through familiarity with Him, nourished by prayer, mediation upon the Word of God and the Sacraments, especially ... Holy Communion".
"Around her strong and genuine personality an authentic spiritual family came into being of people attracted by the moral authority of this young woman. ... Many placed themselves at her service, considering it a privilege to be spiritually guided by Catherine. They called her 'mother' because, as spiritual children, from her they drew nourishment for the spirit. Today too the Church receives great benefit from the spiritual maternity of many consecrated and lay women, who nurture the idea of God in people's souls, strengthen their faith and orient Christian life towards ever higher peaks".
Another characteristic of Catherine's spirituality is associated with her "gift of tears, expression of a delicate and profound sensitivity capable of emotion and tenderness", said the Holy Father. "Many saints have had the gift of tears, renewing the emotion of Jesus Himself Who did not hold back or hide His tears before the grave of his friend Lazarus and the pain of Martha and Mary, or the sight of Jerusalem during His last days on earth. For Catherine, the tears of the saints mix with the Blood of Christ", said the Pope.
Finally he recalled how Catherine of Siena, "though aware of the human failings of the clergy, always had the greatest reverence for them, because through the Sacraments and the Word they dispense the salvific power of the Blood of Christ. The saint invited holy ministers, even the Pope whom which called 'sweet Christ on earth', to remain faithful to their responsibilities, moved always and only by her profound and constant love for the Church". From her, Benedict XVI concluded, "we learn the most sublime science: that of knowing and loving Jesus Christ and His Church".
An excellent book about this amazing Saint and Doctor is Catherine of Siena by Sigrid Undset. Here is the beginning of that book:
The opening pages of Catherine of Siena | by Sigrid Undset, the Nobel Prize winning author of Kristin Lavransdatter | Ignatius Insight 
In the city-states of Tuscany the citizens—Popolani—businessmen, master craftsmen and the professional class had already in the Middle Ages demanded and won the right to take part in the government of the republic side by side with the nobles—the Gentiluomini. In Siena they had obtained a third of the seats in the High Council as early as the twelfth century. In spite of the fact that the different parties and rival groups within the parties were in constant and often violent disagreement, and in spite of the frequent wars with Florence, Siena's neighbour and most powerful competitor, prosperity reigned within the city walls. The Sienese were rich and proud of their city, so they filled it with beautiful churches and public buildings. Masons, sculptors, painters and smiths who made the exquisite lattices and lamps, were seldom out of work. Life was like a brightly coloured tissue, where violence and vanity, greed and uninhibited desire for sensual pleasure, the longing for power, and ambition, were woven together in a multitude of patterns. But through the tissue ran silver threads of Christian charity, deep and genuine piety in the monasteries and among the good priests, among the brethren and sisters who had dedicated themselves to a life of helping their neighbours. The well-to-do and the common people had to the best of their ability provided for the sick, the poor and the lonely with unstinted generosity. In every class of the community there were good people who lived a quiet, modest and beautiful family life of purity and faith.
The family of Jacopo Benincasa was one of these. By trade he was a wool-dyer, and he worked with his elder sons and apprentices while his wife, Lapa di Puccio di Piagente, firmly and surely ruled the large household, although her life was an almost unbroken cycle of pregnancy and childbirth—and almost half her children died while they were still quite small. It is uncertain how many of them grew up, but the names of thirteen children who lived are to be found on an old family tree of the Benincasas. Considering how terribly high the rate of infant mortality was at that time, Jacopo and Lapa were lucky in being able to bring up more than half the children they had brought into the world.
Continue reading...
Also available from Ignatius Press:
• Sermon in a Sentence, Vol. 3 : St. Catherine of Siena - Hardcover
Catherine of Siena is just amazing. When I hear people ranting about women in the Church and how they are second class citizens, I think of this extraordinary young woman, without fear, passionately in love with Our Lord, who virtually singlehandedly restored the papacy to Rome, warning an incumbent Pope in the process, that if he ignored Our Lord, his salvation was at stake!
When I was last in Rome, I prayed at her tomb, in the beautiful church, Santa Maria sopra Minerva. ( yes, she is buried in Rome, not Sienna )
I have a daughter Catherine,a journalist, currently working in Afghanistan, whom I asked this great Saint to lead to heaven.
Posted by: Dr John James | Thursday, November 25, 2010 at 02:23 PM
She is PARTLY buried in Rome. The head was brought back to Siena by her confessor, the Blessed Raymund of Capua.
All the rest of your post is completely true, dear Doctor. My best wishes to your daughter.
Viviana (from Siena, though not from Caterina's native ward )
Posted by: Viviana Castelli | Tuesday, November 30, 2010 at 02:59 AM