The Arachnida and Myriapoda collections at the Natural History Museum are of world-class importance. They comprise over 30,000 jars of spirit, as well as more than 74,000 microscope slides, 180 drawers of dry, pinned specimens, and 40 drawers of spiders egg sacs and nests. Approximately 21,270 species are represented, although this estimate is below the number actually present. The purpose of this paper is to give a brief overview of the early history of the Arachnida and Myriapoda collection, to provide historical information of specific interest to researchers, to discuss the history of the section from 1990 to the present, and to detail all data sources available that relate to the collections, such as accessions registers, collections indexes, card indexes, reprints, databases, and archives. It is hoped that the information contained will provide a useful resource to potential researchers.