ISA has announced that they've released the fourth edition of Ron Dieck's incredibly valuable text on Measurement Uncertainty. Ron's new edition incorporates the uncertainty technologies embodied in both U.S. and international standards with a focus on understanding the strengths and weaknesses of each. The book is designed to serve as a practical desk reference in situations that commonly confront an experimenter. Key topics include the basics of the measurement uncertainty model, non-symmetrical systematic standard uncertainties, random standard uncertainties, the use of correlation, curve-fitting problems, and probability plotting, combining results from different test methods, calibration errors, and uncertainty propagation for both independent and dependent error sources. Examples and problems have been included to illustrate the principles and applications of measurement uncertainty analysis. Sections on the business impact of measurement uncertainty and the treatment of calibration uncertainty are extremely useful additions to the new volume. This book is useful for test, process, and control engineers, as well as researchers, plant supervisors, managers, executives, and all others who need a basic understanding of the assessment and impact of uncertainty in test and experimental measurements. In addition, technical school, college, and university students will find this text useful in gaining insight into the impact of errors in their measurements, as well as estimating the effects of such errors with measurement uncertainty analysis. You can buy the book from ISA, and you can also hire Ron to teach class or do uncertainty analysis for you. I still recall the really acrimonious discussion I had over twenty years ago with the Chief Instrument Engineer of a very large water and wastewater engineering consulting firm over the difference between accuracy, repeatability, and uncertainty. He argued that they were all the same. If you think so, read Ron's book.