This title explores the conception and design of a range of enormous and powerful tanks that came to be designated as 'super-heavy'. The fascinating super-heavy tanks of World War II were heirs to the siege machine tradition - a means of breaking the deadlock of ground combat. As a class of fighting vehicle, they began with the World War I concept of the search for a "breakthrough" tank, designed to cross enemy lines. It is not surprising that the breakthrough tank projects of the period prior to World War II took place in the armies that suffered the most casualties of the Great War (Russia, France, Germany). All of the principal Axis and Allied nations eventually initiated super-heavy development projects, with increasingly heavy armor and armament. Much as the casualties of World War I prompted the original breakthrough tank developments, as Germany found itself on the defensive, with diminishing operational prospects and an increasingly desperate leadership, so too did its focus turn to the super-heavy tanks that could turn the tide back in their favor. Although only a small number of super-heavy tanks were built, much less saw active service, their impressive appearance and specifications - not to mention the possibilities of what might have been - have captured the interest of AFV enthusiasts, historians and military personnel. This illustrated and detailed study explores and compares these designs in unprecedented depth.