Humble Bundle content is DRM-free. Once you pay you get download links in your e-mail for downloading the content. Books are offered in PDF, ePub and Mobi forma

Humble Bundle content is DRM-free. Once you pay you get download links in your e-mail for downloading the content. Books are offered in PDF, ePub and Mobi formats. You can back up the books and/or keep the e-mail for future. If you sign up for an account you can also save your purchase to your account and then access all the purchases made through the library.