This issue of the JCSS contains seven invited papers on database theory. The papers are representative of the latest and most promising research on advancing the state of the art in data management. The following process was used. First, eight papers were carefully selected from among the best research projects published in the top data management conferences during the first half of 2005 (the ...

Yuri Gurevich made many varied and deep contributions to logic for computer science. Logic provides also the theoretical foundation of database systems. Hence, it is almost unavoidable that Gurevich made some great contributions to database theory. We discuss some of these contributions, and, along the way, present some personal anecdotes connected to Yuri and the author. We also describe the h...

More and more often, computational linguists and language engineers need to manipulate large sets of feature structures which constitute real databases. Creating, updating, querying and in general, exploiting such linguistic databases is not an easy task, and it is desirable to have at one's disposal operators and languages for query and manipulation like (and if possible extending) those avail...

The last database theory column initiated a series of articles on the relationship between database theory and practice with a guest column by Is \database theory" an oxymoron? Or is it a platitude? What is the tness measure that decides the survival of ideas (and areas) in mathematics, in applied science, and in computer science? Which ideas from database theory during the past twenty-ve years...