It is still the very beginning of generating a better understanding of what is needed to make an organism tolerate implants, to guarantee the bidirectional communication between microelectronic devices and living tissue or to simply construct an interactive biocompatibility of surfaces in general. This book describes the design, synthesis, assembly and characterization, and the bio-(medical) application of interfacial layers on solid substrates with molecularly or supra-molecularly controlled architectures. Experts in the field describe their contributions that have been developed in recent years.