This useful guide offers a critical appraisal of a theological movement within the church catholic. The authors, a church historian and a systematic theologian, describe Lutheranism as centered in the fundamental principle of the Reformation, justification by faith apart from works of law.The book focuses on the emergence of this chief article of faith as a proposal of dogma to the church ecumenical, its theological formulation, and its significance for the shaping of piety and doctrine. Each issue is treated in terms of both confessional history and systematic theology. Seminarians, pastors, teachers, and interested laypersons of all traditions will gain ecumenical insights as well as pertinent information from this work.