This text is based on a comprehensive study of the literature on posters and poster sessions, a conference held by the International Association of Technological University Libraries (IATUL) on the problems of scientific communication, and on the author's experiences in dealing with posters and poster sessions. A conference poster is described as a means of communication via demonstrative display of facts and ideas through use of drawings, figures, diagrams, photographs, sketches, and other decorative elements on a flat vertical surface. This guide is concerned with the goal of popularizing poster sessions as a new form of conferencing in librarianship, and it also provides assistance for the planning, preparation, conducting, and follow-up of poster sessions, as well as for the preparation and design of conference posters. Sample cataloging entries for conference posters and an extensive list of additional sources of information on poster sessions are included. (THC)