This is a web book, designed to be read on the web (with or without an internet connection). So you can start reading now. But if you’d prefer to have a copy of this book in another format, you can download a PDF in portrait format (7MB) or a PDF in landscape format (19.9MB). There’s also an EPUB version (4.4MB) and a MOBI version (10.4MB).
You can subscribe to a podcast feed of the book via RSS, iTunes, or Stitcher.
Or you can listen to individual MP3 files: Introduction, Foundations, Materials, Visions, Languages.