Figure 1, The Metropolitan Museum of Art, New York, Gift of Phyllis D. Massar, 2002; Figure 2, Collegium Maius, Krakow. Photo © Image Asset Management/World History Archive/age fotostock; Figure 9, Museo delle Scienze, Florence. Photo © akg-images; Figures 10 and 12, Library of Congress, Rare Book and Special Collections Division; Figure 13, The Metropolitan Museum of Art, New York, The Elisha Whittelsey Collection, The Elisha Whittelsey Fund, 1951; Figure 14, Musei Capitolini Roma. Photo © Archivart/Alamy/age fotostock; Figures 15 and 16, A. Mark Smith, “Galileo’s Proof for the Earth’s Motion from the Movement of Sunspots,” Isis 76(1985): 543–51, at pp. 544 and 545, published by the University of Chicago Press; copyright © 1985 by the History of Science Society, Inc.; Figure 18, Library of Congress, Rare Book and Special Collections Division; Figure 19, iStock.com/photooiasson; Figure 20, Lasse Ansaharju/Shutterstock.com.