Author Tom Clancy died on Tuesday in Baltimore. He was 66. Clancy was best known for his military novels like "The Hunt for Red October" and "The Sum of All Fears." The exact cause of his death was not yet known.

According to the New York Times, his writing created a new genre that catapulted him to fame. "With the book's [The Hunt for Red October] publication in 1984, Mr. Clancy introduced a new kind of potboiler: an espionage thriller dense with technical details about weaponry, submarines and intelligence agencies," the report wrote. Business Insider said 17 of his books made it to the top of the New York Times best seller list.

Some of Tom Clancy's books were made into movies and even video games. He co-founded the video game company Red Storm Entertainment in 1996. Ubisoft Entertainment later purchased Red Storm for an undisclosed amount.

In 2002, Clancy ranked number 10 in the Forbes Celebrity List 100. His net worth then was USD 47.8 million. Today, he is estimated to have a net value of USD 300 million, according to Celebrity Net Worth.