There are resellers offering old print versions of Vacuum Tube Amplifier Basics, some for ridiculously high prices. The old print versions were not of the best quality and were printed before the text was checked for grammar. Also, some of the covers may make reference to different revisions; they are all basically edition one with some updates. The current second edition was carefully assembled over several months and is less expensive than the original print versions. In addition, images in the old print books were all black and white. Several images in the new second edition are in color, including the project layout drawings at the back of the book. At $12.00 to download directly from the author, this is one of the best vacuum tube amplifier technical book values available.