William Thomas Gaddis Jr. was an American novelist, born on December 29, 1922, in New York. He is widely considered one of the first and most important American postmodern writers. Over his career, Gaddis authored five novels, the most renowned being The Recognitions, which was named one of TIME magazine's 100 best novels from 1923 to 2005. Two of his other works, J R and A Frolic of His Own, won the annual U.S. National Book Award for Fiction.

Gaddis's writing is characterized by its complexity and depth, and he collected various experiences throughout his life that enriched his novels. He attended Harvard but left mysteriously during his senior year. Working briefly for The New Yorker and engaging in the bohemian lifestyle of the time provided him with vibrant material for his work. He also traveled extensively, visiting places such as Mexico, Costa Rica, Spain, and Africa, and worked in public relations for a pharmaceutical corporation.

A collection of his essays was published posthumously under the title The Rush for Second Place in 2002, and The Letters of William Gaddis was released by Dalkey Archive Press in February 2013. Despite his significant contributions to literature, Gaddis remained a private person, and interviews with him are rare, as he believed that an author might not be the most interesting part of their work.

Gaddis passed away on December 16, 1998, in East Hampton.