The ACM Transactions on Database Systems (TODS) publishes original archival papers in the area of databases and closely related disciplines. TODS welcomes papers on a full range of database research in the management of diverse forms of data. Such subjects include: data modeling, database languages, database theory, query processing, access methods and indexing, security and privacy, transaction management, fault tolerance, distribution, performance, data storage, data mining, and novel applications and infrastructures exploiting database technology. TODS encourages papers that explore the above subjects in the context of large distributed networks of computers, parallel or multiprocessing computers, or new data devices (including data storage devices, data capture devices, and data presentation devices). TODS also encourages papers that describe emerging data-intensive applications that cannot be satisfied by the current database technology. TODS welcomes papers that both lay theoretical foundations for database management and those that provide new insights into the design and implementation of large-scale database management systems, database application development tools, database access interface tools, and database connectivity tools for heterogeneous database systems. TODS also accepts papers that describe user and database administration experiences and issues in large-scale real-world database installations. The emphasis on integration of theory and practice is an attempt to encourage authors of theory papers to consider applicability and/or implementability of the theoretical results, while encouraging authors of systems papers to reflect on the theoretical results that may have been used in building the systems and/or to offer suggestions on issues that may require theoretical treatment. TODS also solicits focused surveys on topics relevant to TODS. These should be deep and will sometimes be quite narrow, but should make a contribution to our understanding of an important area or subarea of databases.