Day 1 of Io is the first of many chapters that will give me that ‘new at programming’ feeling again, where I fumble just trying to build a valid expression that does what I want it to. I actually like that feeling; it means I am learning something new and a web of structures is forming in my mind. I like it almost as much as finally making that first deep connection from a group of new concepts to some of your existing ones, and starting to grasp the parallels. Fortunately for me, that is what this book is all about!