This book is a point of reference for all those who want to learn the cataloguing technique in a library. It is divided into three parts. In the first part, the concept and the function of the catalogue is defined, with the questions related to its nature and aims, as well as the cataloguing techniques and the management of the same catalogue, making reference to the cataloguing theories of various librarians of our time. The second part analyzes the organization of the information in a library including all the elements related to the bibliographic description, the author, title and subject heading and the classification. The Dewey Decimal Description (DDC) and its principles will be particularly analyzed. Eventually, the main two cataloguing standards, FRBR and ISBD, will be described.