'... you received the Spirit of adoption' (Romans 8:15) The relationship between God and his people is understood in various ways by the biblical writers, and it is arguably the apostle Paul who uses the richest vocabulary. Unique to Paul's writings is the term huiothesia, the process or act of being 'adopted as son(s)'. It occurs five times in three of his letters, where it functions as a key theological metaphor. Trevor Burke argues that huiothesia has been misunderstood, misrepresented, or neglected through scholarly preoccupation with its cultural background. He redresses the balance in this comprehensive study, which discusses metaphor theory; explores the background to huiothesia; considers the roles of the Father, Son and Holy Spirit; examines the moral implications of adoption, and its relationship with honour; and concludes with the consequences for Christian believers as they live in the tension between the 'now' and the 'not yet' of their adoption into God's new family.