Functional materials and devices by self-assembly. Self-assembly allows for the development of new paradigms for chemistry and materials science, where various, typically nanometer-sized, objects with precisely engineered sizes, shapes, compositions, and concomitant properties serve as “meta-atoms” or superatomic building blocks for hierarchically assembled materials and devices. The current state of the field reveals that self-assembly is making significant strides toward applications in nanoelectronics, photonics, energy storage, chemical separations, and as a path to form complex structures. The cover shows singlecrystal nanoparticle superlattices assembled via DNA hybridization. The cover image relates to US Department of Navy Award No. N00014-19-1-2213 issued by the Office of Naval Research. The United States Government has a royalty-free license throughout the world to the image. See the technical theme that begins on p. 799.