Ṭhānissaro Bhikkhu (also known as Ajahn Geoff; born 28 December 1949) is an American Buddhist monk and author. Belonging to the Thai Forest Tradition, for 10 years he studied under the forest master Ajahn Fuang Jotiko (himself a student of Ajahn Lee). Since 1993 he has served as abbot of the Metta Forest Monastery in San Diego County, California—the first monastery in the Thai Forest Tradition in the US—which he cofounded with Ajahn Suwat Suvaco.
Biographical information from Wikipedia
Photo from Wikimedia Commons © Sakula (Mary Reinard)