The amphibious operation, one of the most complex operations one can undertake, compriseall services and is regarded as the precursor of today’s joint operations. Though questioned, leading theoretics on the subject are convinced that the amphibious operation´s unique ability to exploit mobility and provide access will remain relevant in the foreseeable future. This thesis examine dominant theories on amphibious assaults and extracts the fundamental principles upon which they rely. These are then tested on two cases, Operation Shingle and Operation Chromite. Robert Leonhard´s Maneuver theory is presented as an alternative theory. The thesis concludes that maneuver theory can explain success where amphibious theory fails. Moreover, Surprise and exploitation thereof seem to be the most valuable principlesfrom the amphibious theoretics. Those two relate closely to maneuver theory´s preemption, dislocation and disruption