Reverse osmosis (RO) is a common buzzword that most people living outside the Third World have encountered, particularly on drinking water bottle labels, as shown in Figure 1.1. It is beyond the scope of this book to discuss the pluses or minuses of bottled water, but it is important to note that the bottled water industry is growing. So, whether the reader is a bottoms-up or kick-the-habit type with regard to bottled water is not the point here. The point is that more and more people are concerned about the quality of their tap water, so they are choosing to purchase and consume bottled water instead. Why do people read the label on a bottle of water? Many read the label to find out the source of the water, what (if any) chemicals were added to the water, and how it was processed or treated. Also, as shown in Figure 1.1, labels commonly include claims about how pure the water is, pointing out that it came from a stream in some high alpine meadow and was filtered and treated by reverse osmosis, all with the intention of impressing potential consumers. Although the term reverse osmosis can often be found printed on bottled water labels and comes up in various discussions about water purification and other industrial processes, it is one of those terms not fully or even remotely understood by the average person. Thus, reverse osmosis joins the growing ranks of other buzzwords (for example, algorithms, benchmarking, fuzzy logic, real-time, podcasting, viral, tagging, and cloud computing and all of its derivatives … private cloud, community cloud, public cloud, hybrid cloud) that we often hear or even use but only vaguely understand or do not understand at all. Sometimes it seems cool or even appropriate to use such terms. Many times our purpose, of course, is to use such terms to make others think we actually understand their real meaning; sometimes we want others to think we are intelligent and well informed, even when we are not.