Abstract
In the thesis we propose FT-ACL, an advanced Agent Communication Language which deals with crash failures of agents running in an open and dynamic MAS. FT-ACL provides high-level fault-tolerant communication primitives and support for an anonymous interaction protocol designed for open MAS. Moreover, the ACL satisfies a set of well defined knowledge-level programming requirements. In the thesis we provide a formal semantics for FT-ACL and a formal specification of the underlying agent architecture.