Book excerpt: This short e-book is written for someone who knows a little math, and wants to understand how our Sun moves across the horizon throughout the year. It shows how to calculate the times of the sunrise, sunset and solar noon. It also explains the mathematics underlying the construction of sundials, and shows how to use a sundial to calculate the correct time as you see it on your watch. Starting with Kepler's first two laws of planetary motion, the e-book guides the reader step by step through the calculations described above. It assumes that the reader is comfortable with trigonometry, polar coordinates and introductory calculus.