Stillman Drake was a frequent contributor to scientific journals. He was the author of Galileo Galilei: Dialogue Concerning the Two Chief World Systems and Discoveries and Opinions of Galileo. C. D. O'Malley was Professor of Medical History at the University of California Medical School. He was the author of Andreas Vesalius: The Bloodletting Letter of I539 and many other books and scholarly articles.

"The authors have . . . placed this gem in its appropriate setting. . . . This excellent contribution to the history of science is much to be recommended." (Nature)

• Introduction-Stillman DrakeOn the Three Comets of the Year 1618-Horatio GrassiDiscourse on the Comets-Mario GuiducciThe Astronomical Balance-Horatio GrassiLetter to Tarquinio Galluzzi-Mario GuiducciThe Assayer-Galileo GalileiAppendix to the Hyperaspistes-Johann KeplerNotesIndex

Stillman Drake was a frequent contributor to scientific journals. He was the author of Galileo Galilei: Dialogue Concerning the Two Chief World Systems and Discoveries and Opinions of Galileo. C. D. O'Malley was Professor of Medical History at the University of California Medical School. He was the author of Andreas Vesalius: The Bloodletting Letter of I539 and many other books and scholarly articles.

"The authors have . . . placed this gem in its appropriate setting. . . . This excellent contribution to the history of science is much to be recommended." (Nature)

• Introduction-Stillman DrakeOn the Three Comets of the Year 1618-Horatio GrassiDiscourse on the Comets-Mario GuiducciThe Astronomical Balance-Horatio GrassiLetter to Tarquinio Galluzzi-Mario GuiducciThe Assayer-Galileo GalileiAppendix to the Hyperaspistes-Johann KeplerNotesIndex

Stillman Drake was a frequent contributor to scientific journals. He was the author of Galileo Galilei: Dialogue Concerning the Two Chief World Systems and Discoveries and Opinions of Galileo. C. D. O'Malley was Professor of Medical History at the University of California Medical School. He was the author of Andreas Vesalius: The Bloodletting Letter of I539 and many other books and scholarly articles.

"The authors have . . . placed this gem in its appropriate setting. . . . This excellent contribution to the history of science is much to be recommended." (Nature)

• Introduction-Stillman DrakeOn the Three Comets of the Year 1618-Horatio GrassiDiscourse on the Comets-Mario GuiducciThe Astronomical Balance-Horatio GrassiLetter to Tarquinio Galluzzi-Mario GuiducciThe Assayer-Galileo GalileiAppendix to the Hyperaspistes-Johann KeplerNotesIndex