Crossposted from https://thebrainbin.org/m/[email protected]/t/1546365
Most of those books seem to be targeted at experienced users, however there are a couple about working with the CLI and one about “how Linux works”. I wish those books were in the lowest tier, it kinda makes sense. Perhaps somebody will find it useful.

Direct link is https://www.humblebundle.com/books/linux-good-stuff-no-starch-books
Humble Bundles ebooks aren’t always DRM-free anymore. But this bundle appears to be.
And I think Electronic Frontier Foundation (EFF) is a pretty important charity to support, for those who can, today.