Calibre does its job so well it's downright essential for anyone thinking about dealing with ebooks. Glad to hear that full text search is added in this version, using it with a bunch of reference books saved will be so useful. It might be worth splitting out the fiction books I have to clean up the results. Maybe it works with tag filtering, I'll have to check.

I’ve long kept separate libraries (including one for academic papers and one for appliance manuals). This search functionality is going to come in quite handy.

Calibre is one of those excellent pieces of software that shows free and open source can sometimes be better than commercial software. My only gripe with it is that it is updated so often [sometimes it seems almost weekly] and every update involves visiting the site and downloading the whole app again. In-place auto-updates would be nice.

I use Calibre along with Calibre-Web [0] to make my library available online, so I can always grab one of my books to read on my phone, whenever I'm stuck somewhere, thumb-twiddling. I have an rsync... command aliased in my terminal. So every time I add new books to Calibre on desktop, I just type that in a terminal and it's immediately synced to my online library.

[0] https://github.com/janeczku/calibre-web

PS: Top marks also to Calibre Dev for actually spelling the name of the app properly. It gladdens my heart no end to see the occasional piece of proper English flotsam still afloat on the massive tide of online Americanisms.

UPDATE: Dammit! --just downloaded and Calibre 6 is OSX 10,15+ only. Another piece of software leaves me languishing, as I stick with Mojave. On the plus side, I'll no longer have to worry about the huge updates I was complaining about above!