Pietro Ubaldi (August 18, 1886 in Foligno, Italy – February 29, 1972 in São Vicente, Brazil) was an Italian philosopher, theologian and teacher.

A descendant of an afluent family of Umbria, Ubaldi renounced richness to be faithful to the gospel.

First he went to Sicily to teach English in a secondary school, then, always as a teacher, he went to Gubbio, where he lived for twenty years.

Since most of Pietro Ubaldi's books are not available in English, titles are only a translation of their Italian versions and might vary once formally published.

1 – Great Messages 2 – The Great Synthesis (Synthesis and Solution to the Problems of Science and Spirit) 3 – Mental Currents (The Nours) 4 – Mystical Ascent 5 – Story of a Man 6 – Fragments of Thought and Passion 7 – The New Civilization of the Third Millennium 8 – Problems of the Future 9 – Human Ascents 10 – God and the Universe 11 – Prophecies (The Future of the World) 12 – Commentaries 13 – Current Problems 14 – The System (Genesis and Structure of the Universe) 15 – The Great Battle 16 – Evolution and the Gospel 17 – The Law of God 18 – The Functional Technique of the Law of God 19 – Fall and Salvation 20 – Principles of a New Ethics 21 – The Descent of Ideals 22 – A Destiny Following Christ 23 – How to Orient One's Life 24 – Christ