Crimson Shadows is the latest in Del Rey's definitive Howard series. The books provide the most authoritative versions of Howard's stories available anywhere, with scholarly notes (in the back, which you need not read, but can be cool to sample) on the original texts.
I have only one caveat about this excellent collection. If (like me) you have previously purchased the previous volumes in the series, namely the Conan, Kane, Kull, and Bran Mak Morn books, then you have already more than half the material in the book. You may find it worth buying anyway, as I did, in order to get Howard stories about lesser known characters (but not written with less passion). Many are well worth the read.
For some one who has not read much of Robert E. Howard, this is a superb place to start. The best Kull story ever (Shadow Kingdom, one of REH's very best) is here. So is the best Bran Mak Morn story (Worms of the Earth). The original version of "The Grey God Passes" is here, etc.
This book is REH at his best. But the overlap with previous volumes in the same series is at least 50%.