ON THE COVER
3D bioprinting of organs. Three-dimensional (3D) printing and related additive manufacturing technologies have started to displace traditional manufacturing in a wide range of industries and applications. This issue of MRS Bulletin highlights 3D bioprinting approaches, including advances and challenges in support materials and multimaterials printing, along with applications in tissue engineering and organs-on-a-chip. The cover shows a 3D printed liver blood vessel network demonstrating the complexity of the challenge in recapitulating the architectural form of living tissue and providing biocompatible environments conducive to cell growth. Image credit: MillerLab at Rice University. See the technical theme that begins on page 557.