Donald Stewart is an Australian hacker, currently completing his computer science doctorate at the University of New South Wales, Sydney. Don has been involved in a diverse range of Haskell projects, including practical libraries such as Data.ByteString and Data.Binary, as well applying the Haskell philosophy to real world applications, including compilers, linkers, text editors, network servers and systems software. His recent work has focused on optimising Haskell for high-performance scenarios, using techniques from term rewriting. He is the current editor of the Haskell Weekly News.