Krzysztof Cwalina is a Principal Architect on the .NET Framework team at Microsoft. He started his career at Microsoft designing APIs for the first release of the Framework. Currently, he is leading the effort to develop, promote, and apply the design guidelines to the .NET Framework. He is a coauthor of Framework Design Guidelines (Addison-Wesley, 2005). Reach him at his blog at blogs.msdn.com/kcwalina.