The document discusses mobile ad hoc networks (MANETs). A MANET is a group of wireless mobile computers or nodes that help forward packets for each other when direct wireless transmission is not possible, such as when nodes are constantly moving or there is no base station infrastructure. Ad hoc networks can be easily and inexpensively established as they do not require a centralized administrator. The document provides a concise definition and overview of the key characteristics of MANETs.