Hi Jonathan, Although I don't believe that any intellectual property issues exist with zLib, who legally warrants that there aren't any? Can you sue the authors or the legal counsel that reviewed the library if they were wrong? FWIW, I think Intellectual property issues are of paramount concern. Ask any corporate counsel in any corporation with a worth of more than $20M, people lose a lot of sleep over this (and corporations spend a lot of time in court over this). Particulary in the areas of compression, encryption, delta comparisons, etc. Although our library doesn't use zLib, I don't see any problem in Stingray utilizing a standard library in their toolkit, unless they aren't being up-front about it. Simply cleaning up the interface and making it easier to use with MFC would be of value, and certainly worth the $495/70 classes = $7 that a developer would pay for it, considering that they *are* warranting it, and are legally liable if there in-fact is an intellectual property issue. In the end of course it is personal choice. Far too often however our fellow developers put code into their applications without thought of its origin, of warranties, and of these legal issues and put themselves and their employers at risk. I have no doubt that companies that are serious about using libraries like zLib (such as Microsoft or AOL) solicit an outside legal opinion on intellectual property issues before including it in anything important. That's how they get their intellectual property protection, from their legal counsel (if they are wrong they can sue their lawyers.) Anyway, legal stuff gives me a headache :) In short, I heartfully say that it is not a non-issue!