Reflections on mercy and compassion by Mother Teresa that have never been released before are to be published in the weeks leading up to her canonisation in September.

A Call to Mercy: Hearts to Love, Hands to Serve by Mother Teresa, who won the Nobel Peace Prize, will be published by Image, an imprint of the Crown Publishing Group, on August 16, AP reported.

The book has been put together by Father Brian Kolodiejchuk, who led the cause for her canonisation. 

Mother Teresa visited the UK in 1992 when she addressed the National Conference of Priests at Birmingham Cathedral. She spoke about the work her religious order, Missionaries of Charity, which she founded in 1950 and has spread worldwide with thousands of sisters, was doing to help Aids victims.

She was born in Skopje in 1910, in the Ottoman Empire, at a time when neither Macedonia or Albania existed. She moved to Ireland and then to India.

A Vatican News report quoted her once as saying: "By blood, I am Albanian. By citizenship, an Indian. By faith, I am a Catholic nun. As to my calling, I belong to the world. As to my heart, I belong entirely to the Heart of Jesus."

Mother Teresa has already been declared venerable and will be declared a saint also on September 4.

Her life was not free of controversy however and there were some vocal critics of her views, her work and the way she carried it out.