The development of a bio-engineered pacemaker is of substantial clinical and also scientific interest because it promises to overcome several limitations of electronic pacemakers. Moreover it may answer the longstanding question of whether the complex structure of the sinus node is indeed a prerequisite for reliable pacemaking, or simpler structures might work as well. This book gives an overview of the current state-of-the-art of creating a bio-engineered pacemaker. It shows the approaches to develop of genetic and cell-based engineering methods suitable to implement them with safety and stability. It also illuminates the problems that need to be solved before bio-pacemaking can be considered for clinical use.