It has been a while since anyone had anything really fresh to say about concurrency control -- a fundamental piece of database technology was widely believed to be "solved". Yet, serious issues remain. Most distributed systems do not operate in transactional mode because the overheads are too high to maintain serializability. With mobile systems that could operate in disconnected mode, it is not even possible.

This refreshing paper introduces the notion of "freshness", and a corresponding notion of relaxed currency for a system in which the user is aware of multiple versions, establishing a firm analytic foundation for a very real practical problem. I expect to see real systems using these ideas in the near future.