She was a student at Hebrew University when, during the summer of 1968, she traveled to Prague and was caught in the Soviet Invasion of Czechoslovakia. Her first-person account of the invasion was published in The Jerusalem Post, where she later worked as a university correspondent for two years. Her early work there determined her career in writing non-fiction.

In 1971, she graduated from the Columbia University Graduate School of Journalism and began writing cultural reportage for the New York Times Sunday edition as well as many national magazines, specializing in profiles of classical musicians including Vladimir Horowitz, Leonard Bernstein and Yo Yo Ma. Several of these are collected in her book Music Talks. and republished under the Authors Guild program Back-in-Print in 2009. She also wrote about the New York Shakespeare Festival and its founder Joseph Papp. Her biography Joe Papp: An American Life is the only full-length biography of the producer. Her profile of art scholar Meyer Schapiro in ARTnews is similarly the only one of its kind.

Epstein is married to consultant Patrick Mehr and has two grown sons, Daniel and Sam. Her books have been translated into several languages and can be found on her website Books Page. She has been a teacher since 1974, was the first tenured woman professor in New York University's Journalism Department. She currently lectures internationally on literary non-fiction, particularly memoir and family history. Her collection of essays on non-fiction Ecrire La Vie will be published in France in 2009 and an American version is in the planning stages.She reviews Berkshire County cultural events online for theartsfuse.com and does occasional bookreviewing for the Philadelphia Inquirer For more specifics see www.helenepstein.com

In 1979, she published her best-known book, Children of the Holocaust, which has since become a much-translated classic on transmission of trauma across generations, used in psychology courses as well as Holocaust Studies. Her sequel to this book is the memoir Where She Came From which has also been widely translated, most recently into Spanish and Italian.

Her biographies of Joseph Papp, producer and founder of the New York Shakespeare Festival Joe Papp: An American Life,and Tina Packer, founder and director of Shakespeare & Company in The Berkshires of Massachusetts reflect her ongoing interest in theater. She is also the translator of Heda Kovaly's Under A Cruel Star, a memoir of life under both Nazism and Stalinism in Central Europe.