William (Bill) Robert Barker is an honorary research associate of the State Herbarium of South Australia.
With Robyn Mary Barker and Laurence Haegi he had a particular interest in Hakea in the family Proteaceae.
In his retirement he is presently involved in outstanding research work, finalising revisions and publications.
Barker is a life member and is the current president of the Australasian Systematic Botany Society.
His primary research expertise is in biodiversity discovery, species and populations and ecological processes.