If you're into security books there's no better publisher than No Starch. For programming books, they do lean heavily towards beginners, but you can say that a

If you're into security books there's no better publisher than No Starch. For programming books, they do lean heavily towards beginners, but you can say that about every publisher. No Starch has a higher percentage of above average and even excellent books than any other publisher I'm aware of. Some are mediocre, but for most publishers 90% of what they put out is mediocre. They have a few great books on low-level programming IMO. They are introductions to that topic but they are topics that I wouldn't consider introductory. Learn you a Haskell and Clojure for the Brave and True are both No Starch. They just don't have the typical No Starch cover.