Many of the classic books are public domain because the copyright has expired. This means that the books are legal to download.

Different sites may have different formats that the books come in. For example, Project Gutenberg usually has Kindle, EPUB, HTML and Text formats. WikiBooks usually has HTML, text and PDF versions available. LibriVox is a site for audiobooks. There are thousands of sites with books, but most free and legal books originate with Project Gutenberg or WikiBooks and are reposted on another site.

Links to Find eBooks (No Login Required)
Project Gutenberg - About 70,000 books are available on this site.

WikiBooks - 100,000s of pages in several languages are available.

LibriVox - A site for free audiobooks read by volunteers.

ManyBooks - ManyBooks is a platform where self-publishing authors have the opportunity to introduce their work. New books are uploaded daily. There are classics too.

Open Library - Has over 20 million records in PDF, ePub, and Daisy formats. Some books can only be borrowed.

Make Your Own Audiobook
A free program that can read books aloud is TypeIt ReadIt. It uses a text-to-speech engine to read text. Text can be copied and pasted into the program for the program to read. Also, the program can save the reading as a sound file.