An apparently not much known and small book, actually encompasses a lifetime of wisdom and understanding on how to make worthwhile pictures; in fact two lifetimes, as it is a dialogue between two friends.
It does not deal with technicality that abounds in other publications, but with the actual taking of photographs, especially how to select a subject, how to shoot it, how to make and use your contacts (applicable also to digital), and how to create a picture essay. Then there is some more, but those four chapters lay a foundation for a way to do photography that is clever, practical, makes sense.
If you ever wonder how to do better than a postcard, or why you reached a plateau after grasping the technique and are not moving further, this book may well be for you.