Paper-based technology. Paper is the newest material that is beginning to transform the device landscape. This issue of MRS Bulletin highlights the use of paper to create novel devices for diagnostics, microfluidics, and electronics that combine low cost and high performance, and how this age-old material is still in its infancy in this context with intriguing applications. The devices shown on the cover are printed electronic circuits layered onto wax-printed fluidic channels. Image courtesy of Jabulani R. Barber. See the technical theme that begins on page 299.