First published as a special issue of the journal Medieval Encounters (vol. 23, 2017), this volume, edited by Josefina Rodríguez-Arribas, Charles Burnett, Silke Ackermann, and Ryan Szpiech, brings together fifteen studies on various aspects of the astrolabe in medieval cultures. The astrolabe, developed in antiquity and elaborated throughout the Middle Ages, was used for calculation, teaching, and observation, and also served astrological and medical purposes. It was the most popular and prestigious of the mathematical instruments, and was found equally among practitioners of various...