Trust management is the process of managing authorization decisions in a decentralized environment where many of the participants do not have reestablished trust relationships, such as logins and passwords, with one another. Trust management is important for enterprise-level and cross-organizational database applications such as supply chain management, enterprise resource planning, and customer relationship management. Trust management research may also interest the database research community because of the former's a?nity for a Datalog-based world, in which a query (authorization request) launches a multi-site search for a proof of authorization. To complicate the process, sites have autonomy and may not always cooperate in proof construction; it is not always obvious where to ?nd the facts and rules needed to construct a proof; and attempts to access particular facts and rules may spawn new authorization requests. © 2008 Springer Science+Business Media, LLC.