The authors of the translation would like to thank Brenda Fineberg for her assistance with this translation. We would also like to acknowledge the indirect support of Google, which made the original Latin version of Torricelli's Opera Geometrica available through books.google.com. The original Latin is also available here. The authors would also like to thank the reviewers, whose meticulous reading of the translation and its preamble found numerous errors and yielded many ideas for improvement.