Dean Wampler is a Consultant, Trainer, and Mentor with Object Mentor, Inc. He specializes in Scala, Java, and Ruby. He works with clients on application design strategies that combine object-oriented programming, functional programming, and aspect-oriented programming. He also consults on Agile methods, like Lean and XP. Dean is a frequent speaker at industry and academic conferences on these topics. *Alex Payne is API Lead at Twitter, Inc. Before Twitter, he worked in information security and built web applications for political campaigns and non-profits. Alex studies and speaks about the design and implementation of programming languages and APIs.