Dr. Peaceman joined Humble Oil & Refining Co. (reorganized as Exxon Production Research Co. in 1964) in Houston in 1951, working in the areas of numerical solution of partial differential equations and the application of computer to reservoir simulation and seismic data processing. He retired as a senior research advisor in February 1986. From then until 2003, he consulted for J.S. Nolen & Associates, Western Atlas Software, and Landmark Graphics Corporation. He is an Adjunct Professor for the Department of Computational and Applied Mathematics at Rice University from 1983 to the present. He is a member of SIAM, Tau Beta Pi, and Sigma Xi. He published a book, Fundamentals of Numerical Reservoir Simulation, Elsevier, 1997 and over 35 articles on reservoir simulation and numerical mathematics. He received the AIME McConnell and Lucas Awards, the SPE Distinguished Member and Reservoir Engineering Awards, was elected to the National Academy of Engineering in 1999 and is an SPE Legion of Honor (50 year plus) Member.