"This is a book on Agile technical practices, principles and values. The readers will first learn individual practices (TDD, Refactoring, Pair Programming, simple design and more). Afterwards they will focus on principles of Software Design, their relationships and systemic reasons, ending with a business oriented and sociotechnical perspective. The authors of the book have been working as software developers and coaches for years, accumulating more then half a century of experience. During this period working in the trenches of teaching software design we created lots of content and shared many stories of real professional life among us. From the feedback we had, we thought it would be a good idea to organize all the information in a single place, following a logical sequence, creating a sort of learning journey. We touch all the principles we consider important to master, dropping too many details."