The works of St. Catherine of Siena rank among the classics of the Italian language, written in the beautiful Tuscan vernacular of the fourteenth century. Notwithstanding the existence of many excellent manuscripts, the printed editions present the text in a frequently mutilated and most unsatisfactory condition. Her writings consist of
the "Dialogue", or "Treatise on Divine Providence";
a collection of nearly four hundred letters; and
a series of "Prayers".
The "Dialogue" especially, which treats of the whole spiritual life of man in the form of a series of colloquies between the Eternal Father and the human soul (represented by Catherine herself), is the mystical counterpart in prose of Dante's "Divina Commedia".
A smaller work in the dialogue form, the "Treatise on Consummate Perfection", is also ascribed to her, but is probably spurious. It is impossible in a few words to give an adequate conception of the manifold character and contents of the "Letters", which are the most complete expression of Catherine's many-sided personality. While those addressed to popes and sovereigns, rulers of republics and leaders of armies, are documents of priceless value to students of history, many of those written to private citizens, men and women in the cloister or in the world, are as fresh and illuminating, as wise and practical in their advice and guidance for the devout Catholic today as they were for those who sought her counsel while she lived. Others, again, lead the reader to mystical heights of contemplation, a rarefied atmosphere of sanctity in which only the few privileged spirits can hope to dwell. The key-note to Catherine's teaching is that man, whether in the cloister or in the world, must ever abide in the cell of self-knowledge, which is the stable in which the traveller through time to eternity must be born again.
1 -[Saint Catherine of Siena]
2 -[Saint Catherine of Siena : The works of St. Catherine of Siena]
Source : EDMUND G. GARDNER, Transcribed by Lois Tesluk in http://www.newadvent.org/