M. Theodore Gresh is president of Flexware, Inc., Grapeville, Pennsylvania, U.S.A. He has been involved in the design of high efficiency centrifugal compressor staging, field-testing of compressors and steam turbines, troubleshooting various field problems including performance problems, rotor dynamics issues, impeller failures and seal problems for over 40 years. While some of this time was in the Technical Services Dept of Elliott Co., Jeannette, PA, USA, he is presently with Flexware, Inc. a company focused on turbomachinery engineering consulting services, training seminars and software for turbomachinery performance analysis. Gresh received a B.S. degree in Aerospace Engineering from the University of Pittsburgh in 1971.