This book describes the BadIdeas method, a tool that aims to nurture creativity and innovation during the design and development of novel user interfaces. The BadIdeas method initially focuses on the generation of bad ideas, which are then submitted to a critical examination. Later, these divergent ideas are transformed until they are of good use and materialise into a tangible artefact or idea for future implementation. Creativity and innovation emerge as fundamental requisites in terms of design and development of present-day user interfaces. While conventional user interfaces need to ensure usability, in addition, less conventional ones require creativity and innovation in order to create engaging and pleasurable experience. In order to nurture these elements throughout the process of design and development of novel user interfaces, the author proposes the use of the BadIdeas method. A review of literature on Human-Computer Interaction, Design and Creativity sets the scene for this work, which then focuses on communicating the iterative development of the BadIdeas method, ultimately forming the major contribution of this research.