The discovery of atomic monolayer magnetic materials has triggered significant interest in the magnetism/spintronics and 2D van der Waals materials communities. Here we review recent progress in this rapidly growing field. We survey the physical properties of the large class of layered magnetic materials, and discuss recent advances in the study of these materials in the 2D limit. We then overview the optical and electrical techniques used for probing 2D magnetic materials (for reading their magnetic states) and the mechanisms for reorienting and/or switching 2D magnets by electric fields (for writing). Emerging device concepts based on magnetic van der Waals heterostructures are also discussed. We conclude with the future challenges and opportunities in this area of research. © 2019, The Author(s), under exclusive licence to Springer Nature Limited.