Bibliography: pages 299-306. / Society never absolutely prohibits homicide: there are "grey areas" in which it is sometimes tolerated or even encouraged. Moral discussion of each area is usually carried on in isolation from the others, and perhaps for this reason, frequently ignores or underestimates the complexities of the morality of killing. This thesis attempts to identify a general method for analysing such issues, so that they can enrich one another. A contemporary theological survey indicates that there should be a balance in Christian ethical method between the polar values of obedience in respect of general standards, and freedom to exercise individual responsibility. This implies recognising a place for intuitions, and specifying a way in which these can be subjected to criticism. In contrast, the Sanctity-of-Life Principle seeks to impose a universal prohibition on the killing of "innocent" human beings. While the Principle provides a useful general guideline, it is deficient as a moral norm - partly because of fatal difficulties associated with the concept of innocence. The method adopted in this thesis is that suggested by Philip Wagaman: methodological presumptions are identified and then tested in a utilitarian way. For the ethics of homicide, I propose a primary presumption favouring the preservation of life, and various secondary and linguistic presumptions. The contextual framework of the thesis is limited to two specific issues - abortion and revolutionary violence.