Glycine: The Gift that Keeps on Giving

Abstract Glycine is a small molecule. It cannot change its conformation and is achiral. Despite the apparent simplicity, glycine shows endless diversity in its behavior over many phenomena. It was the first amino acid for which polymorphism was reported, first on crystallization and then on hydrostatic compression. The polymorphs differ in their physical properties and their biological activity. Glycine clusters persist in solution, leading to “solution memory”. Phenomena at interfaces are critically important for crystal growth, dissolution, and for physical properties, which can be at times unexpected, like polarity in centrosymmetric α ‐polymorph. It is a great pleasure to remind of these remarkable phenomena in a special issue honoring professors Meir Lahav and Leslie Leiserowitz, who pioneered the study of the behavior of this unique molecule in many respects, and showed how complex and non‐trivial phenomena can be at interfaces: between phases and between research fields.