This volume serves as a comprehensive technical catalog documenting the collection of navigational instruments held by the National Maritime Museum in Greenwich. The authors, Richard Dunn and W.F.J. Mörzer Bruyns, utilize their expertise in maritime history and scientific instrumentation to provide a detailed inventory of tools used for celestial navigation. The text establishes a systematic framework for identifying and understanding the evolution of angle-measuring devices from the early modern period through the nineteenth century.

Experts in the history of science and maritime technology regard this catalog as a definitive reference for researchers and museum curators. Readers frequently note the technical density of the prose, which is tailored specifically for those studying the mechanical development of navigational equipment.