This volume contains the significant sixteenth-century texts on the reception and spread of Copernican theory.　Included are the works of Georg Joachim Rheticus (1514-1574): Narratio prima, Chorographia tewsch, Ephemerides novae, Encomium Prussiae, Oratio de astronomia et geographia, Oratio de physica, and Dissertatio de terrae motu et scriptura sacra. In addition, the volume includes the first printed edition of the commentary on the De revolutionibus by Erasmus Reinhold (1511-1553). Furthermore, the volume includes the Notae and the Thesaurus observationum by Nicolaus Mulerius (1564-1630) from the Amsterdam edition of the De revolutionibus (1617).