The first computer scientist was Ada Byron, Countess of Lovelace, in the 19th century. The first to program actual machines, during WWII, were women, too. And the spread-spectrum technology used by cell phones, Wi-Fi and GPS came from the drafting table of a glamorous Hollywood star.

These aren’t the only women who shaped today’s tech-centric world. Throughout the history of computing, women have played a pivotal — if often marginalized — role. Meet some of the women who shaped the world of tech, and learn their stories.

“Dev Divas: Amazing Women Who Shaped Our World of Computer Tech” is a presentation created by software developer Vesna Kovach, whose website celebrates women in the history of technology.