Martin Luther 
Theologia Germanica of Martin Luther 

Martin Luther said that he owed more to the Theologia Germanica than to any other book, next to the Bible and the writings of Saint Augustine. Luther popularized this work by an unknown fourteenth-century German author who focuses on the "divine life, " which is directed or guided by the "true light" of God. A primer in Catholic mysticism, it offers an abundance of insightful spiritual advice, written in simple language and relevant to all Christian denominations. This edition features an informative historical introduction by the translator.