Bookstacks is a personal volunteer project that I began in 2002. Its purpose has always been to provide quality public domain literature, with as little hassle as possible.
Following that philosophy, the actual books are available in the raw directories in which they're stored:
Right-click over any file and select "Save As..." or the equivalent, to save to your hard drive. Left-click to read in your browser.
As you might notice, this site is extremely plain these days. This is to make it as useful as possible on the widest range of devices. I'm currently testing on a 1920x1080 resolution desktop computer, and a 1024x600 Kindle Fire.
If you sort the directory according to date, you can find the most recently updated / added books. I'm still putting the old PDFs into something that looks more normal on a Kindle, so anyone viewing the PDFs with a tablet would probably prefer to download the latest books.
Thank you for coming by. I hope you find this a peaceful island in the chaos of cyberspace.