British Book Trade Index (BBTI)"The British Book Trade Index (BBTI) includes not only printers, publishers and booksellers but also other related trades, such as stationers, papermakers, engravers, auctioneers, ink-makers and sellers of medicines, so that the book trade can be studied in the context of allied trades. BBTI is, however, an index to other sources of information, and is not a biographical dictionary." BBTI covers England and Wales.