Most people already know about Ada Lovelace (in illustration at left), Grace Hopper and the ENIAC programmers of World War II, of course, but many other women have made their mark in technological fields who don’t have the same level of recognition.

In celebration of Ada Lovelace Day, we've compiled an homage to 13 women you might never have heard of but who have made huge contributions to technology or science without quite becoming household names.

Perhaps they will inspire a new generation of women to enter the STEM fields; a smaller percentage of women are earning degrees in computer science now than they were 20 years ago.