The field notebooks are a connection between De Zigno’s field observations and his publications, and undoubtedly, they are a treasure. The field notebooks represent unique evidence of the geo-paleontological activity of this connoisseur of Natural Sciences. Dealing with geological, stratigraphic, palaeontological subjects, and his scholarly relationship with the most important scientists of the time, they give us an exhaustive picture of the development of the Earth Sciences during the second half of the 19th century.