Verify Thema codes for international distribution

This matters mainly if your book will be sold outside the United States and Canada, because a book carrying only North American subject codes may be poorly categorized, or not categorized at all, in a market whose retailers read this scheme instead. If you sell only at home, there is nothing here for you to do. Traditionally and hybrid published authors normally ask whether Thema codes are assigned and what they are; if you publish the book yourself, you check whether your platform offers a Thema field, and some do not, in which case there is nothing to fill in. Find out whether Thema codes are assigned and review them if they are.

These codes decide which category paths your book lands in on retailer sites and, in a physical store, often which section it is shelved in, so a wrong or retired code can leave readers unable to find it by browsing. The codes travel inside the metadata feed, so one choice reaches many channels at once. Traditionally and hybrid published authors normally ask which codes were assigned and raise a concern if the book has landed somewhere wrong; if you publish the book yourself, you choose them in your platform's category fields. Record the current codes assigned to the book and check that they describe what the book honestly is.

If your subtitle is wrong at one retailer, that is one mistake; if it is wrong at a retailer, in a library catalog, and on Google Books, that is usually not three mistakes but one, in the feed, copied three times. It also explains why correcting it in one store often does not stick, because the next feed writes the old value back over your correction. Nobody acts on the feed directly: traditionally and hybrid published authors normally find out who owns it, which is the publisher's metadata or operations team and sometimes a separate distributor, and send corrections there, while a self-published book's feed is generated by the platform from the fields you filled in on its dashboard. Find the person or team that owns the book's feed so a correction goes to the source that can keep it fixed.