Revision with unchanged content. Nowadays, the Internet has opened up new opportunities to share innovations and to collaboratively innovate and modify products and especially software as shown in the open source software movement. Industry and designers have already started to react on this development by supporting end-user involvement in the design and development process. Still the user potential for being innovative themselves is underestimated. This book is aiming to fill parts of this gap by investigating user modifications in the home context, while emphasising how and why users modify interactive systems. A detailed view on recent trends and interdisciplinary theories on user driven modifications is presented and a new approach called „Do-It-Yourself Human-Computer Interaction (DIY HCI)“ is developed. This "do-it-yourself" approach allows people to modify and customize their interactive systems in a more individual and advanced way. People will always engage in areas they are interested in or when they have special needs to solve. Thus, manufacturers will have to provide users more freedom, control and transparency in the interaction with emerging systems or products.