Isaline Blew Horner (also known as I.B. Horner) was born in Walthamstow, England. In 1917, she graduated from the University of Cambridge, Newnham College, with a bachelor's degree in moral sciences (philosophy). In 1921, she went to Sri Lanka (then Ceylon), India, and Burma, where she was introduced to Eastern religions and Buddhist literature. On her return to England, she accepted a fellowship at Newnham College and became its librarian. In 1928, she was named the first Sarah Smithson Research Fellow in Pali Studies and researched and wrote her first book, Women Under Primitive Buddhism (1930). Three years later, she edited her first volume of Pali text, the third volume of the Papancasudani. Among her other works were a translation of the Vinaya Pitaka (Book of the Discipline). She became the Honorary Secretary of the Pali Text Society (PTS) in 1942 and eventually became the Society's President and Honorary Treasurer. She was awarded the OBE in 1980.