There have been many questions and discussions. If you do a search for the keyword "revenue" (as I did here) you just need to scroll down to the US - BOB & Other section to see them.
Otherwise feel free to post your questions/comments in that section.
Welcome to Stamporama!
I don't collect proofs or essays but I can recommend a dealer who specializes in them. http://www.jameslee.com/
I have been dealing with him for the last twenty five years. He is fair and honest. I bought much of my philatelic library and postal history collection from him. He is one of the top dealers in proofs and essays with a large selection of literature. Knowledge is important so keep asking your questions and you will get a lot of information from this site.
