What is your evaluation of the design? I think the design is good. Asio has an easy to use, modern interface that doesn't compromise on portability or performance. What is your evaluation of the implementation? I haven't inspected the code but it sounds pretty impressive that it selects the optimal library for your platform while maintaining a consistent interface. What is your evaluation of the documentation? I found the tutorial easy enough to follow, but I haven't actually implemented anything with the library yet so I can't comment much on the reference section. What is your evaluation of the potential usefulness of the library? Highly. Everyone wants a cross-platform networking library for C++. Did you try to use the library? With what compiler? Did you have any problems? I compiled and ran some of the examples in the tutorial under VC 7.1 with no problems. How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? I've been following discussions from other reviews. I read the tutorial and glanced through some of the rest of the documentation. Are you knowledgeable about the problem domain? I've written my own cross platform synchronous networking library. I've written countless client and server applications mostly under windows, all synchronous. I have no experience actually doing asynchronous IO. I vote to accept asio. Christopher has done a great job, thanks a lot! I'm excited to start using asynchronous IO. I've got server applications that will be pushing the limit on the number of threads soon. I will happily throw out all of my own networking code in favor of this library if it is accepted. My one small concern is that asio rewrites part of Boost.Thread. In the last couple of versions boost has become so easy to install and link against that I don't see the benefit of a header only implementation. Brock