The argument of my thesis concerns the understanding of the doctrine of sin in systematic theology, and, as a corollary of this, the scope of the doctrine in terms of its content. My argument is that the doctrine of sin is particularly prone to being defined with a strictness or narrowness which causes it to lose much of its meaning; that such limiting treatment tends to be accompanied by distorted relationships with, or over-determination by, other key doctrines, particularly that of salvation; and that it is helpful to see this tendency as a failure to see sin as a symbol with a complex of meanings, this complex being essential to the doctrine. A brief introductory survey of the usual perspectives on sin and of recent monographs firstly indicates the major issues raised by sin. Then more detailed analysis of the work of Barth, Brunner, Rahner, Pannenberg and Ricoeur provides examples of different methods of dealing with sin and leads to the conclusion that the tension between freedom and inevitability is essential to the doctrine of sin: it is part of sin's meaning and attempts to suppress, explain or relocate it lead to unacceptable tensions elsewhere. The use of Ricoeur's analysis of the symbolism of evil as a critical tool demonstrates the significance of the Adamic narrative for Christian doctrine, and the way in which its neglect can lead to the acquisition of ideas characteristic of non-Christian mythologies. The positive suggestion of the thesis is that sin should be seen as a tensive symbol incorporating a wide complex of meanings and involving a specific mythology of "the beginning" and that its paradoxical nature should be maintained as indicating a conflict within humanity, and seen in relationship to the suffering of God in Christ.