Ted Dunning is Chief Applications Architect at MapR Technologies and active in the open source community.He currently serves as VP for Incubator at the Apache Foundation, as a champion and mentor for a large number of projects, and as committer and PMC member of the Apache ZooKeeper and Drill projects. He developed the t-digest algorithm used to estimate extreme quantiles. T-digest has been adopted by several open source projects. He also developed the open source log-synth project described in this book.Ted was the chief architect behind the MusicMatch (now Yahoo Music)and Veoh recommendation systems, built fraud-detection systems forID Analytics (LifeLock), and has issued 24 patents to date. Ted has aPhD in computing science from University of Sheffield. When he's notdoing data science, he plays guitar and mandolin. Ted is on Twitter as@ted_dunning.