Edward Henning (1949–2016) was a leading Western authority on Kālachakra, having studied for decades with Tibetan masters of the Jonang tradition in particular. A mathematician by profession with an interest in computer programming and journalism, Henning applied his expertise to Tibetan calendrical systems with Kālacakra and the Tibetan Calendar (AIBS, 2007). Some of his essays on Kālachakra and related topics remain available at his website, www.kalacakra.org.