Green Templeton College Vice-Principal Dr Rebecca Surender will introduce this year’s Astronomy For All Lecture, delivered by Associate Fellow Charles Barclay. This illustrated talk will highlight the pivotal and unsung role played by women in astronomy and astrophysics. It has been 100 years since the death of Henrietta Leavitt, the discoverer of the Period-Luminosity law for Cepheid variable stars, from which Edwin Hubble was able to measure the scale and expansion of the Universe. The talk will review the importance of Leavitt’s work and also single out three other women, whose 20th Century contributions, in their respective fields, have been critical to the development of the whole subject.