This book introduces a novel mobile robot design concept aimed at exploration of subterranean spaces. The key innovation is the combination of highly maneuverable body elements with wheel/leg elements. This combination offers performance not possible with conventional monolithic wheeled or tracked mobile robots, or with current robot snakes. The book covers four design iterations of the concept, concentrating on describing the overall design process and results from field tests. Additionally a kinematic analysis of the fourth prototype and implications for future designs is presented. With this book you will have a general overview of the state of the art in mobile robots for exploration of rough environment as well as a deeper analysis of the design of a new concept in vehicle locomotion.