Dan Tow is an independent consultant, operating under the banner SingingSQL (www.singingsql.com). His experience solving Oracle-related performance problems goes all the way back to his 1989 hire by Oracle Corporation. During most of his tenure at Oracle, Dan focused on the performance of Oracle Applications, managing the performance group for that division. In this role, he found a fertile testing ground for his SQL tuning method applied to the huge set of complex SQL included in those applications, including both online SQL and diverse batch processes. In 1998, Dan left Oracle to lead performance for TenFold Corporation, where he applied the same methods to tuning questions on DB2, and… SQL Server, and Sybase, as well as on Oracle. In 2002, Dan started his own business, SingingSQL, through which he offers diverse database-related tuning services, including SQL tuning and systematically analyzing load to learn which SQL should be tuned. He has introduced his SQL tuning method to over 1,000 people in short lectures, and now offers in-depth courses in the material, using this book as textbook. Dan has a Ph.D. in chemical engineering from the University of Wisconsin at Madison. He lives in Palo Alto, California, and can be reached at dantow@singingsql.com.