Symposium M, 'Materials and Technology for Nonvolatile Memories', was held November 30-December 5 at the 2014 MRS Fall Meeting in Boston, Massachusetts, which was a follow up of previous symposia on nonvolatile memories. Main research areas featured in Symposium M were advanced Flash memories, organic memories, resistive switching memories (ReRAM), magnetoresistive random access memories (MRAM), ferroelectric random access memories (FeRAM), phase-change memories, as well as emerging materials and technologies for nonvolatile memories. In addition, a highly successful one-day tutorial session, 'Emerging Materials and Devices for Nonvolatile Memories', was conducted and included tutorials on ReRAM, polymer/organic materials, MRAM, and Flash memories. This symposium proceedings volume represents the recent advances and related material issues on various kinds of nonvolatile memory technologies. The papers in this volume are categorized according to each type of memory technology and are not in the order of the symposium presentations.