Molecular self-assembly is the process by which molecules adopt a defined arrangement without guidance or management from an outside source. Molecular assembly into well-defined nanoscopic/meoscopic structures plays a significant role in nanobiological and nanomaterial sciences, and thus has attracted a great deal of attention in both fundamental and applied studies. This book presents current research in the study of molecular self-assembly, including directed molecular assembly on metal surfaces; controlled self-assembly of macrocyclic molecules based on calixarenes in functional supramolecular entities; the self-assembly, chirality and polymorphism of bacterial flagellar filament; self-assembly as a key process in bottom-up technologies from nano to microscales; and the supramolecular helix formation from designed peptides coded and non-coded amino acids.