Project Gutenberg has free downloads of public domain works in .txt .html and .epub formats. They were all created by volunteers over the past 15+ years. These aren’t high quality digital books, but they are free and without DRM, so you can read them on just about any device.
Scribd is a service where users can upload their own documents to share with others. You can download those documents or embed them into your website. Not all of the documents are books, but there are lots of books included.
This site has all legal free downloadable ebooks. I couldn’t find anything on the website saying which formats the ebooks are in, but my guess is that most are PDF.
This is a small but growing collection of free ebooks. Downloads are either PDF or ePub. Some are samples but most are full books by modern authors.
MemoWare has a ton of documents and files that are formatted for different devices. They used to advertize devices like Palm and Pocket PC, but now their website says their files also work on Kindle and Nook.
Amazon has an entire section of their website with free Kindle ebooks.
Adobe has a collection of free sample ebooks that you can download for Adobe Digital Editions. They are PDF and ePub formats.
Free ebooks organized into categories. Some are online and some are links to other websites for a download.
This is a big index of free books that you can find online or for download in PDF format. You could kind of consider it a Wikipedia for free ebooks.
Here is a great free online personality test that will help you find out your personality type according to the Myers Briggs theory based on Jung.
With the free account option you can get access to HTML ebooks and up to 5 downloads in PDF or TXT.
A lot of people are interested in getting ebooks from their local libraries. That is clear just by reading the comments on this website, as well as from the big news that the Kindle now supports library ebooks.
Many people who own e-readers might be interested in this, but not know where to begin. I found this video at PCWorld that walks you through checking out an ebook from the Boston Public Library:
Obviously you will need to check with your own local library, but as far as I know most of them use the same system provided by Overdrive, so the process at your library will probably be very similar.
This was already possible on e-readers like the Sony Reader, but it was a feature that the Kindle lacked until very recently. There is more information in this blog post from ZDNet.
There are many places to find free ebook downloads online, but there are a few big, reliable, places where you can get a ton of free ebooks safely and easily. Here are my favorites:
I recently wrote up an overview of how you can use the Google eBookStore. The ebooks come in PDF and EPUB for a variety of different devices with the Google Books app, or use on the web. Go directly to the free ebooks.
eBookMall has a section devoted to free ebooks. All are ebook downloads that are totally free. It seems like some are only available for a limited time, as a promotional effort by authors or publishers.
Project Gutenberg has been around for a long time. They started with OCR scanning of public domain books into .txt files, and now they have available HTML, ePub, Kindle, and more.
Amazon Kindle Store
You can get a ton of ebooks for free from Amazon in Kindle format. Like the paid ebooks, you can use them on a Kindle device or in a Kindle app for your computer or other devices. Go to amazon.com/kindle-ebooks/ to get to the Kindle eBook Store, then find the Top 100 Free listing on the right side of the page, a little ways down.
These ebooks aren’t downloadable, but there is a nice selection of classic popular texts that you can read free online. Useful for school projects or study, if they have what you need.
The BeBook store has 20,000 free classic titles available for download. The free ebooks come in plain text and PDF, and can be used on any computer or device.