The version of the Documentation Treaty we publish here reproduces the original published in 1934 at the Editions Mundaneum in Brussels. We have chosen to upload not only the full HTML version of this famous treaty, but also, for the first time, the reconstruction (layout, fonts), in PDF text format, of the original written by Paul Otlet. We attached a preface by Olivier Le Deuff and a postface by Bertrand Müller. ___ This book is devoted to a general presentation of the concepts relating to the Book and the Document, and to the reasoned use of the elements which make up the Documentation. The Book and the Document need to be rationalised, starting from an initial unit, extending to increasingly large groups of units, eventually encompassing all existing units or units to be built, by an organisation which envisages, at the base, the individual documentary entity, which forms the sum of their books and papers for each person. This book provides a general outline and a coordinated approach. The main aim of this Treaty is to identify facts, principles and general rules and to show how coordination and unity can be achieved. This coordination, this unit, the International Institute of Bibliography, the International Office attached to it, the Institutes cooperating at the World Palace, the Mundaneum, have been working since their foundation in 1893, 1895 and 1920 to study them, define them and make them a living and tangible reality. The international congresses of these and other bodies have already decided on an important set of regulatory data. The aim is to prepare for new cartels, new standardisation and new works to be jointly established and punished.