In these [Apologies] Justin gives no formal or logical exposition, scarcely even an outline, of a complete Christian system. His purpose is merely to collect arguments to justify fair and equitable treatment of the Christians by the authorities, and to support his demand that they should not be condemned unheard. With this object he seeks to refute the popular calumnies against the Christians, he insists on the excellence and truth of the Christian teaching and on the effects which it produces, and he struggles to prove the claims of Christ, especially by the argument from the fulfilment of prophecy. Thus, although he is dogmatic to a degree exceptional among Apologists, owing to the fact that he concentrates his argument round the Person of Christ, yet it is futile to seek in the Apologies for a formulated system of Christian theology.
--from the Introduction