Looking for a "Tube Guide"

I am trying to find a resource where I can learn about tubes - types, uses, prices, pros, cons, etc. Can anyone recommend anything - online or offline?? Thanks!!
A few that I'd recommend would be "Tube Lore" by Ludwell Sibley...."Tube Substitution Handbook" by William Smith...RCA Recieving Tube Manual.."70 Years of Radio Tubes and Valves" by John Stokes You can buy these at www.tubesandmore.com
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