For bodybuilders and fitness enthusiasts, changing body composition often reflects hard work and discipline—but knowing body composition is useful for anyone, and for more than just bragging rights.

Thanks to the ever-improving world of fitness trackers and apps, you've never had more access to personal health data. But which of the dizzying number of markers and metrics should you really be ...

We're sharing our best tips on how to photograph the moon and with the total lunar eclipse on March 13-14 — discover the right gear, settings and composition techniques to make the most of the event.