Four women whose pioneering contributions to science have been largely overlooked.

Ethel Browne Harvey and Hilde Pröscholdt Mangold did pioneering research in embryology, Ida Henrietta Hyde helped develop the first microelectrodes for the stimulation of single cells, and Marthe Gautier had a vital role in discovering that Down syndrome is caused by an extra copy of chromosome 21. So why are their names so little known by the scientific community at large?