Abstract—A distributed system is a collection of spatially separated processes that communicate over a network and coordinate their actions by exchanging messages. Because of the failure-prone nature of the network and the processes themselv es, many complex problems arise in distributed systems. If not addressed, these problems can prove to be significantly costly to applications  that involve communication and coordination betw een multiple processes. Many of these problems can be overcome through the use of fundamental algorithms for ordering, coordination, and agreement. This paper will review some of these algorithms, including synchroni zation, ordering of events, mutual exclusion, election, multicast, consensus,  and Byzantine Generals Problem.