BISAC began as a standalone initiative, designed to create standards for EDI transmissions in the book supply chain, largely between ordering departments and warehouses. BISAC was responsible for a file format called “BISAC fixed” as well as another called “X12”. With the rise of book superstores such as B&N, Borders, and Books a Million, it became apparent that a standard was needed to determine where in these stores books should be shelved. BISAC took on the responsibility of creating standardized codes that publishers could use to suggest to bookstores which section of a store a book would be a good fit for.
Initially there were only a handful of codes. By 1995, there were around 50 general codes, with a few “sub-codes” under each – forming a 2-level hierarchy. The codes were rather cryptic – 3 letters followed by some numbers – because they were developed for machine-to-machine processing. The actual names of the codes were only used by those doing the assigning and those receiving the books and deciding where to put them. (There were those nerds who had the codes memorized, because there were so few of them.)
But with the emergence of online retailers, BISAC experienced a period of rapid change. It was subsumed by the Book Industry Study Group, which had originally been created as a research community analyzing the book market. And BISAC codes were developed with an eye towards discovery on the web as well as in-store placement of books. Whereas bookstores required a single BISAC code, web stores could “shelve” a single book in multiple categories. Most guidelines recommend 3-5 codes per title.
You might notice, for example, that the “Body, Mind and Spirit” BISAC categories begin with the characters “OCC”.
This is because that category used to be called “Occult” back in the 80s and 90s. It was where books about UFOs, spiritual healing, crystals, Wiccans, and other titles were shelved. The OCC prefix evolved into the “New Age” category. As “Body, Mind and Spirit”, it has been expanded to includes books about mindfulness, meditation, reiki, “inspiration and personal growth”, and fengshui, all of which are fairly mainstream, in addition to continuing with more obscure topics such as astrology and numerology.
So if the BISAC prefix doesn’t match up to the name of the category itself, it probably had a previous life as a category more appropriate for the 80s or 90s cultural landscape. Books reflect our landscape, and their subjects evolve over time.