The book is about the evolution of 'Augustinianism' in a process of 'spiritual transvaluation' as Augustine of Hippo's thought was appropriated by spiritual masters in the medieval period. The chapters deal with a range of experiences in 'spiritual transvaluation' beginning with Augustine's own philosophic transvaluation of Christian 'affectivity'. The first study is about St. Gregory the Great's 'pastoral' transvaluation of Augustine's spirituality; the second about William of St. Thierry's 'mystical' transvaluation in the twelfth century; and the final one is about Walter Hilton's 'christo-centric' transvaluation, writing as an Augustinian Canon Regular in late fourteenth century England. The Epilogue draws together the themes of each chapter as a reflection about the spiritual nature of 'Augustinianism'.