There is currently no shared language of vocation among Catholics in the developed, post-modern world of Europe and North America. The decline in practice of the faith and a weakened understanding of Church teaching has led to reduced numbers of people entering into marriage, religious life and priesthood. Uniquely, this book traces the development of vocation from scriptural, patristic roots through Thomism and the Reformation to engage with the modern vocational crisis. How are these two approaches compatible? The universal call to holiness is expressed in Lumen Gentium has been read by some as meaning that any vocational choice has the same value as any other such choice; is some sense of a higher calling part of the Catholic theology of vocation or not? Some claim that the single life is a vocation on a par with marriage and religious life; what kind of a theology of vocation leads to that conclusion? And is the secular use of the word 'vocation' to describe certain profession helpful or misleading in the context of Catholic theology?