This article presents results of a research conducted to discover the origins of the Paulo Barreto (João do Rio) Library, a section in the Portuguese Reading Chamber of Rio de Janeiro. Several original documents up to this date unknown to the scientific community were used as the evidence source. The approach is inserted into the realm of Collections Formation and Development since knowing the history of the collections that make up a library helps understanding the history of the library. The article also aims to provide information for further studies about writer and journalist Paulo Barreto. Using printed and manuscript sources the article tries to explain the process of donation of these books and their reception by the Chamber's members. It includes a sample list of authors present in the collection, analyzes the organizational form of the acquisition and infers that the organization of the books today is the same adopted by its original owner.
João do Rio; Real Gabinete Português de Leitura; Private library; History of libraries
