An open-source project under Wikimedia, which includes publicly available books, historical documents, poems, speeches, legal texts, and other original manuscripts.
Wikimedia Digital Library
Click the "Visit Site" button on this page to open the official Wikisource website, then follow its on-screen instructions.
Wikisource is accessed online through your browser, so there is usually no local installation. Refer to its official site for details.
You can browse comparable reading sites under the e-books category on this site and pick the one that fits you.