The book "Flexible and Stretchable Electronic Composites" offers a comprehensive collection of electronic aspects of various types of elastomer composites. It addresses the combinations of synthetic, natural, and thermoplastic elastomers with different conductive fillers such as metal nanoparticles, carbon nanotubes, and graphene. These elastomer composites are particularly useful for electronic applications and cover both chemical and physical as well as materials science aspects. The materials presented have great potential to meet new requirements in material applications, especially in the field of flexible and wearable electronics. The book is structured according to the type of rubber/elastomer, with each chapter describing a different elastomer matrix and its composites. It provides a solid introduction to the fundamentals and discusses current challenges in this research area.