Berkeley—Leonard Cottrell III, of Berkeley, California, passed away on May 4, 2016.

Leonard was born on October 8, 1937, in Ithaca, New York, to Leonard Jr. and Anita Cottrell. He married Anne Ginzton on March 3, 1964.

Leonard was passionate about helping people all over the internet gain a deeper understanding of physics and cosmology. He was constantly thinking about how better to explain a concept in terms that a layperson could grasp. He was equally passionate about poetry, especially poetry in foreign languages, which he would often translate. He sang bass in several Bay Area choruses over the years.

Leonard is survived by his wife Anne; son Ben, sister Susan Woolson and her children Jonathan and Robin, Erika and Katie, and an increasing number of their children Lydia, Georgia, and Jameson, as well as by his brothers-in-law and sisters-in-law Leonard and Cheryl, Nancy, David and Linda and their children Katherine and Greg, LaTisha and Tom, Matt and Vanessa, Claire and Nick, Nate and Jennifer, and Chris, and their children Taylor, Tavis, Laila, Charlie, Caleb, Dominic, Jacinda, Fisher, Greta, Max, and Oliver.