Non-print materials entered the mainstream of collection development in libraries in the last two decades. Audio, visual and audio-visual materials are found to be excellent supplements to printed packages (textbooks, workbooks, manuals, etc.) for teaching and learning in schools and colleges and in other instructional and training institutions. Films, filmstrips, slides, audio tapes, records, etc. are used in conjunction with conventional instructional materials with good results. This gives opportunities to many enterprising business companies to invest in these areas. These business firms have largely chosen to concentrate on one aspect of the field of non-print materials and to develop and refine it.
Moreover developments in the educational set-up and advances in information technology have offered new scope to libraries for storing and retrieving information through the newer media such as computers, microforms and other electronic devices. This has led to the practice of building collections in microforms of backfiles of periodicals, newspapers and other types of less used materials thus saving valuable storage space. Online access to data and information through computer networks accentuated the advantage of using these newer media in libraries. Collection building in libraries in industrially advanced countries place equal emphasis on no-print materials, although in developing countries, only a beginning has been made to think in these directions. There are also no specialised agencies which produces these type of materials while there are agents for procuring them from countries where they are produced and marketed.
Non-book materials, particularly microforms and audio visual materials, are produced by firms specialising in microfilms and microfiches and those specialising in educational teaching and learning materials respectively. Machine readable databases are produced by major publishing agencies like American Chemical Society, Institute of Scientific Information, Engineers Joint Council and such others, in their respective field of specialisation. Library wholesalers stuck these materials, particularly audio visual material and supply them. These producers advertise their wares largely in professional periodicals and other publications and occasion-ally bring out catalogues, promotional materials like folders, pamphlets etc. Video cassettes, tape-slide kits are available for machine readable data bases like chemical abstracts, citation index etc., helping the process of use. All these provide good facilities to know these non-print materials, and decide on their acquisition,
In addition to modern physical media, electronic media have arrived and changed the concept of a library's role in society. These include the magnetic media - magnetic tape, magnetic disk, floppy disk - and the optical media - CD-ROM, WORM, etc., - and rewritable magnets optical disk, etc. Increasingly, these are being produced by firms and are being acquired by modern libraries due to the many distinct advantages they possess and also because they have become one of the key elements in ensuring effectiveness of libraries and information centres.