Experimental stress analysis is an important tool in the overall design and development of machinery and structures. While analytical techniques and computer solutions are available during the design stage, the results are still dependent on many assumptions that must be made in order to adapt them to the problems at hand. One popular method of finding structural and design weaknesses is through the use of the electrical resistance strain gage. These devices are relatively low in cost, easily applied by a reasonably skilled technician, and require little investment in instrumentation (for the general user), yet they yield a wealth of information in a relatively short time period. The information and its validity is, of course, dependent on the training and knowledge of the engineer who plans the tests and reduces the data. In addition to serving as a reference for engineers, this practical, instructive book has a high potential as a textbook for senior and first-year graduate students in engineering and related fields, such as engineering physics and geology.