Is Knopp's Theory and Application of Infinite Series out of date? It's looks terrific to me, but the Dover edition I bought new maybe a year ago: http://preview.tinyurl.com/2eprqps seems to be the same as an edition published in 1951 and may go back as far as 1921. 60 or 90 years is a lot of math years. How about it? Does my book leave out some important developments? Is it old-fashioned in some other ways?
I've seen this question: what is the current state of the art in methods of summing "exotic" series? but it doesn't have a full answer yet.