Robert X. Perez is a practicing mechanical engineer in the petrochemical industry with over 40 years of experience. He has written extensively about machinery reliability in process settings.Heinz P. Bloch has carried out long-term assignments as Exxon Chemical’s Regional Machinery Specialist for the United States. He has authored or co-written over 770 publications, including 24 comprehensive books on practical machinery management, failure analysis, and more.