Welcome to the fascinating world of web development! As we begin our journey towards HTML5 development, we'll take the time and review the past. After all, you can't really get anywhere unless you know where you're coming from. Unless you have been living under a rock for the past several years, you have certainly heard a lot about Web 2.0, the Open Web, and definitely HTML5. If you have heard those terms from, say, three different people, you will probably have also heard at least three different definitions of each. For this reason, we will briefly describe what those terms mean, why you should be excited about them, and how HTML5 is a game changer.