Zotero is great for keeping an inventory of your books. Super easy to add books just by entering the ISBN and sometimes tweaking the fetched entry a little. I

Zotero is great for keeping an inventory of your books. Super easy to add books just by entering the ISBN and sometimes tweaking the fetched entry a little. I always export the books we have to a spreadsheet file for reference on my smartphone when we're going to a second-hand book fair.