LOUIS THEODORE, EngScD, is a retired professor of chemical engineering (50 years). He is the author of several Wiley publications, including Fluid Flow for the Practicing Chemical Engineer, Thermodynamics for the Practicing Engineer, Mass Transfer Operations for the Practicing Engineer, and Air Pollution Control Equipment Calculations. Dr. Theodore is also a contributor to Perry's Chemical Engineer's Handbook.J. Patrick Abulencia is an Associate Professor in the Department of Chemical Engineering at Manhattan College. He received his B.S. degree in Chemical Engineering from Manhattan College, and his Ph.D. in Chemical and Biomolecular Engineering from Johns Hopkins University. Dr. Abulencia typically teaches material and energy balances, thermodynamics, fluid flow, and unit operations laboratory. His research interests include water filtration, life cycle assessment, and engineering education. He co-authored with Louis Theodore Fluid Flow for the Practicing Chemical Engineer.