Looking for a "Tube Guide"

Yes: Go to Audioasylum.com and cruise through the "tube" and "set" forums. Once you get aquainted the site has a full search feature which will allow you to research specific types. Just keep in mind that these are opinions and not gospel.

At Http://www.TheTubeStore.com -- In addition to selling a very large selection of tubes, they have a information section on tubes and tube basics that has a lot of good information.

An online resource is available at "http://www.svetlana.com/". Understanding that I am a beginner in tube audio, it is probably not up to par with the references listed by Longplate, but I found some of the basics offered there interesting.

There are numerous good books of a tubular nature available from Parts Connection division of Sonic Frontiers website.

Didn't VTL have tube book? Seems like I saw one in the Audio Advisor catalog. Good Luck, Doug