"This fine translation is a god-send. . . . Surely you want to read what Galileo wrote. If so buy this book. Van Helden's introduction is scholarly; no one knows more about Galileo's telescope; the translation is superb; Van Helden's review of the reception of the Sidereal Messenger is profound; the bibliography is extensive. What more can I say?"—David W. Hughes, The Observatory "[Sidereus nunclus] has never before been made available in its entirety in a continuous form, with full notes and comment. The introduction, translation and notes by Van Helden are a splendid example of the best scholarship and fullest accessibility. . . . we can now truly get to grips with the phenomenon of Galileo and what his life and work should mean to us today."—Robert Temple, Nature