After obtaining his degree from the University of Berlin and passing the theological examination of the Evangelical Church, Dietrich Bonhoeffer made his vicariate or practical apprenticeship in the Evangelical Community of Barcelona, ​​where he stayed between February 1928 and February 1929. From that step are written of both biographical and theological value that meet for the first time in Spanish in this edition. A first set of texts are the three lectures given under the title "Necessity and hope in the current religious situation", which seems to respond to the appeal made by Karl Barth in his commentary on the Letter to the Romans: «Say and do ... what we should now say and do in order to live up to the need and hope of the Church ». In these public interventions it is already expressed what was the constant of Bonhoeffer's life: to attend, with theological demand, to the requirements of the present time. The preaching, on the other hand, a compendium of his work as a pastor, stands out for the richness and depth of the ideas presented and the security of his ideas. What is also there for the young preacher, and eminently, is to update the word of God, showing in his scandal the strength of salvation here and now. The letters, finally, convey the circumstances of the stay in Barcelona and are the vivid portrait of a sociable and industrious Bonhoeffer, but also with a pronounced sense of loneliness and leisure. In them the reader will find information about their way of life, their activity and their trips through Spain, as well as their personal impressions of the city and the country, of its people, their art and literature and their parties. Letters are added here your diary entries and documents relating to your vicariate, among other texts.