Best Resource For US Paper Money?

I guess I am old fashioned, but I use Paper Money of the U.S.(now the 20th ed.) by Arthur and Ira Friedberg. To me this book puts the currency in a more easier way to read than that website. The website above does have great information about serial numbers and blocks that the book doesn't have.

And I agree with DoubleEagle20. That book has always been the Bible for US Paper Money collecting, and it keeps improving every issue, both new and long time collectors can learn from that book.

It's where the F numbers originated from and just about all dealers use it, pricing is a bit if-fey but you have better more up to date sources for that such as the bigger auction houses and e bay, most anyone that does not have a copy to study is probably not that interest in currency collecting.
Bill Collector

In agreement with Friedberg. It's pretty much the " Red Book" standard for US paper.
For prices I take an average of Friedberg and good websites that get recommended to me via this forum, such as http://www.uscurrencyauctions.com/