Trade Literature:

Trade literature consists of documents that give information on the processes and materials involved in the manufacture of a product, various types of product catalogues, compilation of trade data, manuals, guides, house journals, etc. Trade literature is issued by manufacturers and dealers. The basic purpose is product advertisement. These documents normally  provide accurate technical information about products and materials that are offered for sale. This information is usually not available from tinny other source. In a special library, trade literature is an important source of information. 

The information contents of trade catalogues include details about uses, size and specification of products, the range of the products of a firm, properties of materials, design data, test results, operating instructions, etc. However, trade catalogues become obsolete quickly and are superseded by newer catalogues.