This webpage, part of a larger project “Understanding Chemistry”, provides a solid introduction to UV-vis spectroscopy suitable for use in introductory chemistry and introductory analytical chemistry courses. The UV-vis pages discuss UV-vis light, absorption, Beer’s law, the double-beam spectrometer, and introduce some standard applications of UV-vis spectroscopy. Explication is clear and thoughtful. Judicious and effective use of graphics. Site is easy to navigate, and the links work. Some typos.