Nearly two years after her tragic death, author Michelle McNamara's final book was published today.

To much of the world, McNamara is best-known as the late wife of Patton Oswalt. But she had her own outstanding career as a nonfiction writer long before they met.

At the time of her death, McNamara was working on an investigative book about the Golden State killer. That book, "I'll Be Gone In The Dark," was finally published on Tuesday. Oswalt, who wrote the book's afterword, was instrumental in helping guide it to completion. Though McNamara had finished much of it before passing away in her sleep, Oswalt leaned on friends and colleagues to bring it home. "It was her book and it’s an amazing book," he said. "I wanted to do right by her."