<B> </B>The approach taken in this book is to approach vacuum systems from a pressure regime viewpoint. That is, after covering some basic chemistry, the first pressure regime covered is the rough vacuum regime. Within the study of rough vacuum systems, the following topics are covered: the gas load, the pumping mechanism, pressure measurement and vacuum system construction. The discussion of rough vacuum is then followed by the study of high-vacuum systems. The same topics are revisited, but this time from a high vacuum perspective. Once both rough vacuum and high vacuum systems are covered, then the topics of leak detection and residual gas analysis are introduced. This approach lends itself to laboratory experimentation. During the review of gas laws from chemistry, there are a number of experiments and demonstrations that can be performed to reinforce basic laws and concepts. Then, during the study of rough vacuum systems, pumpdown times can be calculated and pumpdowns performed in the laboratory. Likewise, during the study of high-vacuum systems, pumpdowns as well as other lab exercises, such as outgassing and residual gas analysis, can be conducted. <B> </B>Coverage of vacuum systems from a pressure regime viewpoint, rather than from a topical viewpoint. Focus on the fundamental science behind vacumm system components. <B> </B>This book is written for users of vacuum systems, especially the technicians that are responsible for maintaining them.