This book highlights the preparation and characterization of efficient electromagnetic shielding composites containing bio-carbon derived from natural loofah with unique three-dimensional porous structures by means of entire structure design of composites according to shielding theory. The synergistic effect of multifunctional nanoparticles and bio-carbon on electromagnetic shielding mechanism, mechanical performance, and thermal stability of composites obtained has been holistically investigated. The discovery of this renewable, environmentally friendly, and inexpensive bio-carbon represents a new class of conductive materials with multi-interfaces and unravels further research and development of a wide variety of new electromagnetic shielding material systems with potential commercial applications ranging from electronic devices to energy management.