Leonard Harold Zeskind (born November 14, 1949) is an American human rights activist, researcher, journalist, and anti-racist expert renowned for his work on white nationalist, far-right extremist, and white supremacist movements. He founded and serves as president of the Institute for Research and Education on Human Rights (IREHR), a nonprofit organization focused on monitoring racism, antisemitism, and social justice issues in the United States. Zeskind's career began in the 1970s as a labor organizer and anti-Klan activist while working as a welder in Kansas City, Missouri. His investigative work has exposed networks of white supremacist groups, contributing to broader efforts against hate extremism through reports, congressional testimony, and publications in outlets like The American Prospect. Zeskind's seminal book, 'Blood and Politics: The History of the White Nationalist Movement from the Margins to the Mainstream' (2009), provides a detailed chronicle of the evolution of white nationalism in America, earning him recognition as a leading authority on the subject. He has collaborated with organizations such as the Southern Poverty Law Center and has faced personal threats from the extremists he studies. Throughout his decades-long activism, Zeskind has emphasized the intersections of race, politics, and economic inequality, advocating for public policies to counter far-right influences. As a prominent voice in anti-racist research, Zeskind continues to lecture, write, and engage in watchdog activities, underscoring the ongoing threats posed by domestic extremism in contemporary society.