This issue of MRS Bulletin focuses on materials that enable nanofluidic systems with unusually high mass fluxes, termed “enhancement factor” or “slip flow.” There is now ample evidence of such flow enhancement in nanochannels, with sizes ranging from subnanometer to a few nanometers. Most of the studies to date, both experimental and modeling, have focused on carbon nanotubes and, more recently, on graphene. Different fabrication methods result in different structures, surface chemistries, and defects, with a significant effect on flow enhancement. As new one-dimensional and two-dimensional nanomaterials are synthesized, a deeper understanding of the nanoscale transport physics is needed, particularly in the relationship between material properties and flow behavior. Herein, authors at the forefront of experimental, modeling, and theoretical developments in nanofluidic flow describe the state of the art in materials development and characterization.