Publisher Summary This chapter explains Moore’s Law. To understand why ubiquitous computing is particularly relevant today, it is valuable to look closely at an unexpected corollary of Moore’s Law. As new information processing technology gets more powerful, older technology gets cheaper without becoming any less powerful. First articulated by Intel Corporation founder Gordon Moore, today Moore’s Law is usually paraphrased as a prediction that processor transistor densities will double every two years. Moore’s insight was dubbed a law, like a law of nature, but it does not actually describe the physical properties of semiconductors. Instead, it describes the number of transistors Gordon Moore believed would have to be put on a CPU for a semiconductor manufacturer to maintain a healthy profit margin given the industry trends he had observed in the previous five years. In other words, Moore’s 1965 analysis, which is what his law is based on, was not a utopian vision of the limits of technology. Instead, the paper described a pragmatic model of factors affecting profitability in semiconductor manufacturing. Moore’s conclusion that “by 1975 economics may dictate squeezing as many as 65,000 components on a single silicon chip” is a prediction about how to compete in the semiconductor market. It is more of a business plan and a challenge to his colleagues than a scientific result.