The book follows five 'circles' around the painting (consciously evoking the circle of thorns held behind Christ's head). Each circle looks in turn at the subtexts of the painting, explored by Bosch:
(1) politics What is the interplay between religion and power, and what assumptions do we make about their relationship today?
(2) science, or elements What is the proper relationship of science and religion in our own day? Is Dawkins the last word on the matter, or does Bosch give us a way of expressing, with renewed confidence, a religious understanding of science?
(3) temperaments What challenge does Bosch's painting pose to our personality, and to our modern understanding of human psychology?
(4) devotions What was the spiritual atmosphere of Bosch's day, and how does it relate to our own?
(5) the final circle, Quiddity, centres on the still subject of the painting: Christ himself. It asks what meaning we can find in the Incarnation and Passion today, and shows how we can transform our understanding of trust and time and their implications for proclaiming the Gospel. The book is not a work of art history, although its art historical conclusions are sound. It draws on writers and artists from Thomas a Kempis to Terry Pratchett, and from St Bonaventure to Bob Dylan and Brian Eno to show how a painting "500 years old but passionately modern" can transform our understanding of what it means to be fully human.