To read on Windows, Mac, or Linux:
Download Calibre, the free open-source ebook reader and ebook management software. Open it up and there’ll be an “Add Books” button in the left hand corner. Use that to add books you’ve downloaded (either Kindle or EPUB format is fine). They’ll appear in the list in the center of the Calibre window. Click on them to read them.
To read on Android or iOS devices:
Download the Kindle app and register it with your Amazon account. On your PC, download the “Send to Kindle” app (Google it to find a version for your operating system). Download Kindle versions of books. Once all of the above are complete, you should be able to open your downloads folder, right-click the downloaded books, and see a “Send to Kindle” option. Clicking that, you’ll have the option to select which Android devices you’ve registered should receive the book. It’ll upload to the Amazon cloud and then get sent down to those devices.
Alternately, there are a variety of e-reader apps that can work with epub files.
To read on Kindle:
Download Kindle files to your PC and use Send to Kindle as described in the Android/iOS section.
Buy yourself a Kindle
Kindles (by which I mean the Paperwhite or the original Kindle, not the Kindle Fire series) have a number of advantages:
- Easy to use with MTP stuff and other Project Gutenberg books (Send to Kindle)
- My battery usually lasts a week on a single charge
- Screen size is comparable to an ordinary page (larger than a phone but smaller than a monitor)
- Screen works well even in direct sunlight
- Having a reading-focused device avoids the distractions that pop up on a phone, computer, or general-purpose tablet
- Annotations and highlights are pretty user-friendly and convenient
- Virtually everyone who sells ebooks sells for Kindle
I don’t think any other device combines these advantages. (There are other e-readers out there, but so far as I can tell none of them have the kind of backing and long-term viability that Kindle gets from Amazon.) I was a skeptic for years, but when I finally broke down and bought a Kindle I paid for it within a few months with the money I saved by getting free Project Gutenberg books and cheap e-books rather than buying physical copies.