This study revisits Gabriel Naudé's foundational contributions to librarianship, particularly as outlined in his Avis pour dresser une bibliothèque. As one of the earliest proponents of professional librarianship, Naudé redefined the role of librarians and set principles that continue to influence modern library practices. Unlike his predecessors, who organized collections as an adjunct to monastic, noble, or royal duties, Naudé approached librarianship as a structured, professional pursuit. His work with patrons like Henri de Mesme and Cardinal Mazarin provided Naudé the resources and platform to experiment and apply his theories on collection development, organization, and public accessibility in libraries. Notably, he advocated for the establishment of large, accessible libraries, thus anticipating the modern public library system. Naudé's Avis covered essential elements of library science, from cataloging and organizing books by subject to maintaining a balanced collection that includes multiple perspectives on controversial topics. His suggestions on purchasing works in diverse fields, including lesser-known and even heretical subjects, reflect his commitment to intellectual diversity and open-mindedness. This stance was progressive for his era, especially given his close association with powerful figures in the church and state. Naudé believed that a library should serve as a comprehensive repository of knowledge, where materials from a range of disciplines and viewpoints are available to foster a well-rounded scholarly environment. Though the Avis was not widely circulated initially, its enduring influence is evident. Naudé's recommendations on cataloging, loan supervision, and ensuring public access to collections during designated hours laid the groundwork for many practices still prevalent in library administration. His work was later translated into English by John Evelyn, who praised its practical insights and educational value. Avis pour dresser une bibliothèque remains a significant historical text in library science, embodying ideals that championed free access to knowledge, organized classification, and the preservation of historical records for future generations. This title is part of UC Press's Voices Revived program, which commemorates University of California Press's mission to seek out and cultivate the brightest minds and give them voice, reach, and impact. Drawing on a backlist dating to 1893, Voices Revived makes high-quality, peer-reviewed scholarship accessible once again using print-on-demand technology. This title was originally published in 1950.