Book excerpt: Centuries of exploration and discovery have documented the diversity of life on Earth. Records of this biodiversity are, for the most part, distributed across varied and distinct natural history collections worldwide. This makes the task of extracting and mobilising the information within these collections an immense challenge.ÿÿIn this special issue of ZooKeys, 18 papers by 81 authors examine progress and prospects for mass digitising entire natural history collections. These papers provide a snapshot of activity, in what is a fast moving field that is seeing ever-increasing degrees of collaboration across disciplines and between collection-based institutions. Examples of research covered by these articles include a description to efforts digitise 30 million plant, invertebrate and vertebrate specimens at NCB Naturalis in the Netherlands; new scanning and telemicroscopy solutions to digitise the millions of pinned insect specimens held in the Australian National Insect Collection and its European and North American counterparts; citizen science projects being used to crowdsource the transcription of thousands of specimen labels and field notebooks; and new data portals providing central access to millions of biological specimens across Europe.ÿÿMany of these projects deal with the unique challenges associated with major collections that have built up over several centuries, with different communities of practices and different user communities. Despite many differences, standards for collection acquisition, preservation and documentation are broadly consistent, meaning that there is sufficient common ground to bring together the enormous amounts of data that are being exposed through mass digitisation efforts. These data will become the new frontier for natural history collection management and research in the next decade.