Pentecostals and charismatics today are not known for placing great emphasis on the blood of Jesus, yet such was not always the case. Even a cursory reading of the popular literature produced by the earliest Pentecostals reveals that the atonement generally, and "the blood' in particular occupied a central place in their spirituality. Indeed, during the first two years of British Pentecostalism, the mere mention of 'the precious blood' appears to have had, for them, an almost magical power to make the devil flee and induce the experience of baptism in the Holy Spirit. In this thesis, I have attempted to tell the story of when and how this emphasis on the blood of Christ began and progressed, culminating in early British Pentecostalism. The claims of this piece of research are limited to demonstrating, firstly. that there was continuity. There is an identifiable tradition of this style of spirituality that passed from generation to generation, especially within Evangelicalism, which reached its apogee in the earlier years of Pentecostalism. Secondly. I demonstrate that there was change. The different forms that the tradition took in response to changing conditions are described and analysed and the gradual disappearance of the tradition from within Pentecostalism is noted with possible reasons being offered. I have concluded this thesis by pointing out, firstly. the part these findings could play in opening up a discussion of the Christological roots of Pentecostalism. This aspect of Pentecostal origins could speak into current debates about Pentecostal identity that draw much from its distinctive pneumatology but which presently see less that is distinctive or identity depicting in its Christology. Secondly. this piece of work supplies resources that may be found useful in the wider Evangelical debate about the atonement. One common objection raised against the doctrine of penal substitution is that it does not obviously point the way to the ethical or spiritual transformation of the individual. In this thesis. a significant body of evidence is presented that shows how many individuals, almost entirely subscribers to a penal view of the atonement found ways of making their atonement theology personally transformative. Thirdly, this thesis offers a collection of data that may be found useful by those researching the interaction between Christianity, especially in its more radical forms, and the cultural forces brought to bear upon it.