The Cosmos of Design is a journey through the characteristic features of design thought processes that usu-ally occur unconsciously. With the help of simple examples, designing is explored step by step: Creative experimentation and speculative thinking are highlighted in addition to cognition-oriented tests, iterative loops and abductive conclusions. The result of this study is a coherent pattern of thought, an enlightening philosophy of design. As a resource for students and practitioners, The Cosmos of Design is intended to broad-en the understanding of design and to provide theoretical foundation and practical inspiration.