Valentin Weigel's theology of mystical speculation represented the culmination of German mysticism in the 16th century. Traditional schools of thinking of various origins are united in Weigel's works. His Protestant-spiritualist piety, which was influenced by Sebastian Franck, drew upon medieval mysticism, primarily upon Eckart, Tauler and the ›Theologia Deutsch‹. His thinking incorporated Boethius' neoplatonist ideas and Paracelsus' ideas on natural philosophy, and he developed them into Christological-cosmosophical speculations. The continuing influence of his thinking, which often emerges unexpectedly, such as for example in the works of Johannes Arndt und Kepler, has presented researchers with many unsolved problems, in particular regarding Böhme's relationship to Weigel and to Weigelianism. They will be able to be solved on the basis of this Weigel edition, which also includes the writings attributed to him. This first complete critical edition of Valentin Weigel's works is based on seminal research done by Winfried Zeller. His study of the handwritten works which have been preserved made it possible to resolve the previously contentious issues regarding the question of authenticity, to determine which writings were definitely done by Weigel, as well as their chronology, and led to the discovery of previously unknown manuscripts.