Keith A. Jenkins was a Research Staff Member at the IBM Thomas J. Watson Research Center from 1983 to 2018. In this position, he had the privilege of working with device development, technology evaluation, and circuit design, leading to research in a large variety of device and circuit subjects. These include high frequency measurement techniques, electron beam circuit testing, radiation-device interactions, low temperature electronics, SOI technology, substrate crosstalk in circuits, frequency response of nanoscale devices and studying the impact of self-heating in advanced CMOS technologies. He also worked to design circuits for analog on-chip self-measurement, including jitter and phase error measurement, and on-product reliability monitoring. He designed several compact and efficient structures to measure device performance, uniformity and device reliability, in order to replace the discrete transistor structures usually used for these studies. In pursuing these research goals, he developed many new measurement techniques, some of which are covered in this book. He received several technical awards from IBM, and several best paper awards from conferences and journals. He received a PhD in physics from Columbia University for experimental work in high energy physics, and before joining IBM, he worked in high energy physics at The Rockefeller University. He was an adjunct professor of physics at Hunter College and Manhattan College. Dr. Jenkins is now engaged as a consultant on the subject of semiconductor device and circuit measurements.