Jim is a Technical Fellow at Microsoft working in the San Fransisco office of MicrosoftResearch.
Jim has forgotten more about transaction processing than most of us will ever know. See Transaction Processing: Concepts and Techniques (http://www.amazon.com/exec/obidos/ASIN/1558601902).
Here's his official bio from MSR (http://research.microsoft.com/~Gray/):
Jim Gray is a researcher and manager of Microsoft Research's eScience Group. His primary research interests are in databases and transaction processing systems -- with particular focus on using computers to make scientists more productive. He and his group are working in the areas of astronomy, geography, hydrology, oceanography, biology, and health care. He continues a long-standing interest on building supercomputers with commodity components, thereby reducing the cost of storage, processing, and networking by factors of 10x to 1000x over low-volume solutions. This includes work on building fast networks, on building huge web servers with CyberBricks?, and building very inexpensive and very high-performance storage servers.