This object group only samples the devices relating to plane trigonometry in the Smithsonian collections. Separate object groups discuss spherical trigonometry, mathematical tables, sectors, slide rules, rules, desktop electronic calculators, and handheld electronic calculators. Printed sources include not only manuals mentioned here but an array of maker’s catalogs and specific texts. For a general historical discussions of early trigonometry, see:
Van Brummelen, Glen, The Mathematics of the Heavens and the Earth: the Early History of Trigonomery, Princeton: Princeton University Press, 2009.