Clive Cussler has died. According to a report from TMZ, the author -- known for his novel Sahara, which served as his most successful film adaptation -- passed away Monday. The outlet, citing Cussler's son, reported that his cause of death is unknown.

The author was prolific, writing dozens of books throughout his career, both fiction and non-fiction. Many of his novels followed the adventures of Dirk Pitt, an adventurer and veteran of the Vietnam War who served in the United States Air Force. Pitt was the protagonist of 1992's Sahara, a character who was brought to life by Matthew McConaughey in the 2005 film of the same name.

In real life, Cussler was himself a veteran of the USAF who served in the Korean War. He attained the rank of sergeant and worked as an aircraft mechanic and flight engineer. After the military, Pitt worked for the National Underwater and Marine Agency (NUMA), a fictional organization that Cussler brought to life in 1979.

As the founder and chairman of the private non-profit NUMA, Cussler oversaw an initiative seeking to "uncover and explore historically significant shipwrecks before they are lost and gone forever."

"Our goals include the protection of these historic sites through public information programs and to make available archaeological reports and data on technical expertise while perpetuating the names and legends of the sea-loving men and women who came before us."

NUMA has located, or attempted to locate, an exhaustive list of shipwrecks and is credited with dozens of positive identifications. The organization maintains a special interest in ships from both the Union and Confederate navies from the American Civil War.

Cussler did not put on airs however, saying he did not fancy himself an expert when it came to his work with NUMA.

"I have never made claim to being an archaeologist. I'm purely a dilettante who loves the challenge of solving a mystery; and there is no greater mystery than a lost shipwreck."

Cussler was born on July 15, 1931, in Aurora, Illinois. He married Barbara Knight in 1955 and the two remained together until her death in 2005. The couple had three children together -- Teri, Dirk, and Dayna. Teri founded and manages the Cussler Museum, which houses the author's collection of classic cars -- "100 of the finest examples of custom coachwork and 50's convertibles to be found anywhere."

After Barbara's death, Cussler later married Janet Horvath.

According to the FAQ on his official website, Clive Cussler Books, he first began writing 1967, working on his books at night and on weekends. This is contradicted in the bio section of the Clive Cussler Books site, which states he started writing in 1965. He published the first Dirk Pitt novel in 1973.