The dialogue is a Christian mystical work by St. Catherine of Siena (1347 - 1380) who is said to have composed it while in " state of ecstasy while in dialogue with God the Father."
The book is a dialogue between the God the eternal father and the human soul of St. Catherine. The dialogue relates, by the means of many metaphors, the spiritual life of humanity, emphasizing the importance of virtue, constant prayer and obedience.

The dialogues have been a classic since they were composed in Italian in the 14th century.
St. Catherine herself was a powerful figure of her time. She was given to severe penances and is said to have manifested stigmata on her body. She laboured personally with prayer and works of mercy throughout her life and is famous for playing an instrumental rule in healing "the great schism of the West," when there were a number of popes claiming to govern the Roman Catholic church. St. Catherine was canonized in 1461 and declared a doctor of the church in 1939.