A consulting engineer residing in Montgomery, texas, Heinz. P. Bloch has held machinery-oriented staff and line positions with Exxon affiliates in the United States, Italy, Spain, England, The Netherlands, and Japan. His career spanned several decades prior to his 1986 retirement as Exxon Chemical's regional machinery specialist for the USA. Since his retirement from Exxon, he has been in demand throughout the world as a consultant and trainer in the areas of failure avoidance, root cause failure identification, and reliability improvement. Mr. Bloch is the author/co-author of thirteen books and over 200 other publications on subjects related to machinery reliability and failure avoidance. He is the Reliability and Equipment Editor of Hydrocarbon Processing magazine and has served as chair of the annual conference program for Hydrocarbon Processing's Process Plant Reliability Conference for a number of years.John J. Hoefner is a mechanical consultant specializing in reciprocating and centrifugal compressors, engines, turbines, and pumps. He is the former chief engineer of Worthington Service Corporation.