Mary Trump’s explosive tell-all memoir about her uncle, President Trump, is already a massive hit.

Too Much and Never Enough: How My Family Created the World’s Most Dangerous Man sold 950,000 copies on its first day of sale, USA Today reports. That’s a new record for publisher Simon and Schuster.

Simon and Schuster CEO Jonathan Karp said, “There is only one word that can be used to describe the sales of Mary Trump’s memoir and that word is HUGE,” invoking one of President Trump’s favorite adjectives.

Mary Trump’s book has also proved popular among critics, including one for Kirkus, who described the book as “dripping with snideness, vibrating with rage, and gleaming with clarity—a deeply satisfying read.”

Karp said that Too Much and Never Enough “has entered the national conversation in a way that few books ever do, becoming a cultural phenomenon and must-read for anyone seeking to understand the singular family dynamic that produced the most powerful man in the world today.”

Mary Trump has been busy promoting the book. She appeared on Good Morning America this week, telling George Stephanopoulos that she thinks her uncle should resign from the presidency. And Business Insider reports that on Thursday, she appeared on Rachel Maddow’s show, where she claimed she had heard President Trump use the “N-word.”

The success of Mary Trump’s book shows no sign of slowing down. As of Friday afternoon, it was the No. 1 bestselling book at Amazon and Barnes Noble.

Michael Schaub is a Texas-based journalist and regular contributor to NPR.