Dietrich Bonhoeffer is without question a hero of the Christian Faith, and one would be well served to study his thoughts, theology, commitment and example. But this is probabaly not the place to start, for two reasons.
(1) The writing style of this book is badly outdated and hard to follow and understand. This book badly needs an editor to put Bonhoeffer's thoughts into more modern prose. This book, as it is, is a difficult and at times convoluted read. A new updated editon is badly needed.
(2)Secondly, and more importantly, this book is early Bonhoeffer,full of didactic thought, at times morally pompus. A better place to start a study of Bonhoeffer might be his last work, "Letters from Prison..." written at the end of his life. this work is the more seasoned, more mature Bonhoeffer, a man who has seen to some the degree the mistakes and folly of his earlier thinking.
Case in point: In this work, Bonhoeffer says to be a disciple a man must separate himself from the everyday living of life. In the later book, "Letters from Prison," he writes, it is "only by living completely in the world that one learns to have faith..." He says he stands by his earlier book because he wrote it, it is his work, but he makes it clear that if he had it to do over again, his thought would be different and he would express himself in a way much more understanding of the world in which we live.
For that reason, "Letters From Prison..." would be the best place to get the complete, aged and wise Bonhoeffer.