David Graeber, the anarchist intellectual whose early efforts in Zuccotti Park made Occupy Wall Street an era-defining movement, died Wednesday. He was 59.

An outspoken advocate of anti-capitalist causes, Graeber figured prominently among the initial group of activists who, in anticipation of the later occupation, organized the New York City General Assembly. During the crucial six weeks that led up to the encampment, he helped to establish the principles of direct democracy that came to define the Occupy moment. “David’s first meetings with activists in New York were critical,” remembers co-founder and editor-in-chief Kalle Lasn.

“Without him, Occupy Wall Street would not have happened.”

In addition to his dedicated activism, Graeber was a renowned academic and author of acclaimed books such as Debt: The First 5,000 Years (2011) and Bullshit Jobs: A Theory (2018). At times, his adherence to anarchism attracted controversy. Yale University did not renew his professorship in 2005, cutting short his hopes for tenure. More than 4,500 of his peers, students, and other supporters signed petitions decrying Yale’s decision, some alleging that his political beliefs were a factor. Signatory and fellow anthropologist Maurice Bloch called Graeber “the best anthropological theorist of his generation from anywhere in the world.” As of 2013, Graeber was a professor of anthropology at the London School of Economics.

Graeber died of as-yet unknown causes, in Venice. He is survived by his wife, artist and writer Nika Dubrovsky.

David Graber’s writing was featured in issues #82 and #83 of Adbusters.