Analysis of cracks on masonry buildings proves to be quite difficult, and so sometimes expert's scientific knowledge cannot be enough to do so, a vast experience is needed, built on practice gained through field work, phenomenons observation and testing during a long professional career. On this matter, needs to be noticed that the majority of pictures present on this book comes from authors' personal archives, collected during an intense and wide job experience. In practical terms, often it is needed to diagnose, within a very short time, a building dislocation and/or having to find out the causes, in order to find urgent solutions or definitive remedies, all involving a huge amount of responsibility, especially on serious cases where there is not much time and hesitations could be fatal. In this book are shown dislocations and crack patterns actually observed, which would turn surely useful to other experts on the building field.