Susan Wojcicki, the former boss of YouTube and one of Google's earliest employees, has died aged 56.
Google's chief executive Sundar Pichai announced that Ms Wojcicki had passed away after two years of living with lung cancer.
Mr Pichai, who is also the boss of Google's parent company Alphabet, said on X/Twitter he was "unbelievably saddened" and Ms Wojcicki was "as core to the history of Google as anyone".
Once described as the "most important Googler you've never heard of", Ms Wojcicki was present at the company's beginnings when, in 1998, she rented out her Menlo Park garage to the search engine firm's founders, Sergey Brin and Larry Page.
She was later persuaded to leave her job at chip giant Intel to join Google, becoming the firm's 16th employee.
Ms Wojcicki would go on to lead YouTube, the online video sharing company owned by Google, for nine years until 2023 when she stepped down to focus "on my family, health and personal projects I'm passionate about".
Ms Wojcicki was one of relatively few women to hold a senior role in the technology industry.
She wanted to encourage more girls to go into the field, telling the BBC's Newshour in 2013 that the future was going to be "increasingly digitally influenced".
"But then I see there are very few women in the industry," she said. "Overall the tech industry has, on average, probably about 20% women and I also look at the pipeline of girls coming out of technical degrees and it is very small."
While Ms Wojcicki rose to become the boss of YouTube, her tenure was not without controversy. The platform faced criticism over its handling of online disinformation, including during the Covid pandemic.
In 2022, a number of fact-checking organisations wrote to her accusing YouTube of being "one of the major conduits of online disinformation and misinformation worldwide".
Ms Wojcicki stepped down a year later to focus on her personal life and health.
Announcing her death "with profound sadness", her husband Dennis Troper said: "My beloved wife of 26 years and mother to our five children left us today after two years of living with non-small-cell lung cancer."
