During the period 1550-1650, the Spanish monarchy faced military challenges that put at stake its European hegemony. Having learned from the maritime wars, the Spanish changed their paradigm of maritime warfare. As a result, the main maritime shipping force in the Spanish kingdom, the Basque merchant shipbuilding tradition, was no longer a suitable navy to defend the Imperial interests. This led to a shipbuilding transition to suit a more militarized type of design, although Basques found alternatives to their traditional merchant endeavours, reaching their shipbuilding peak by the 17th century. This book challenges traditional historiography and shows an alternative story through the cultural view of Basque shipbuilders, heterogeneous but interconnected to contemporary traditions, such as the Portuguese. Basque shipbuilding was a unique tradition in its making, belonging to a wider Euro-Atlantic network of culture and technology.