This is a historical book. The design of the following treatise, and the occasion which elicited it, are indicated both on the title page and in the introduction of the work itself. Its primary object is not to discuss the obligation of Synods to adopt the doctrinal basis of the Platform. What we felt it a duty to the church to publish on that subject, we have presented in the Lutheran Observer. But the pamphlet of the Rev. Mann, entitled Plea for the Augsburg Confession, having called in question the accuracy of some of the interpretations of that Confession contained in the Definite Synodical Platform, and affirmed the Scriptural truth of some of the tenets there dissented from; it becomes a question of interest among us as Lutherans, which representation is correct. For the points disputed are those, on the ground of which the constitutions of the General Synod and of her Seminary avow only a qualified assent to the Augsburg Confession. In hope of contributing to the prevalence of truth, and the interests of that kingdom of God which is based on it, the writer has carefully re examined the original documents, and herewith submits the results to the friends of the General Synod and her basis. Since these results as to the question, what do the symbols actually teach? are deduced impartially, as must be admitted, from the original symbolical books themselves, as illustrated by the writings of Luther, Melancthon, and of the other Reformers of the same date; those who approve of those books should so far sustain our work: and those who reject these tenets, that is, the New School portion of the church, will not object to seeing a vindication of the reason why they and the General Synod avow only a qualified assent even to the Augsburg Confession, namely, because these errors are there taught.