Summary: Why is spherical trigonometry a lost art? What is "Heavenly Mathematics" about and what background is needed to learn the material? To you spherical trigonometry is an exquisite branch of mathematics. How so? What calculations could be performed accurately a few hundred years ago, or earlier? What techniques are used to determine the size of the earth, or the distance to the moon? What is the most elegant theorem of spherical trigonometry? How is spherical trigonometry important today in the context of modern technology? Is there a next book? What advice would you give to a parent whose child was struggling with math?
