This book is addressed to students and teachers in design degrees and researchers interested in logical thinking of design. Just like any other discipline, design must accredit its rational fundamentals to refer the conditions of knowledge that determine it as a specific object of study. Methodology is a bridge between the general principles of doing and knowing. The analysis of the design theoretic fundamentals involves an approach to its models as well as the conceptual assumptions. Likewise, it establishes the indissoluble relationship between theory, method and technique, that thinking and doing present in their necessary unit.