Book Owners Online (https://bookowners.online), an e-publication of the Bibliographical Society, was launched as a freely available directory of historic English book owners in August 2020. A Zoom symposium at 5.30 pm (London time) on Tuesday 9 February 2021 will explore its purpose and plans, and invite wider engagement – brief presentations by David Pearson, Clodagh Murphy, David Shaw and Sarah Cusk will be followed by discussion. The event is open to anyone interested, and registration is free.