Tom Petty’s fittingly titled first posthumous release, “An American Treasure,” was released Sept. 28. “An American Treasure” is a compilation box set of rarities, B-sides, live versions and other songs from his solo career and songs from the Heartbreakers and Mudcrutch, his first band, which eventually became the Heartbreakers.

The past two years have been rough for music fans. American rock legend Petty died Oct. 2, 2017, due to cardiac arrest from an accidental drug overdose, according to CNN. Petty appealed to listeners of all generations, and his music is a part of American culture and has been since his arrival.

This release is by no means a greatest hits album; neither “Free Fallin’” nor “Learning To Fly” are anywhere to be found, but this doesn’t make the album any less monumental. The album plays less like a collection of Petty’s hits and more like an archive of songs that demonstrated his musical prowess. The majority of material on “An American Treasure” was unheard before its release.

Despite the 63 tracks coming from such a wide span of Petty’s career, the compilation runs very smoothly. The album has been remastered under the supervision of producer Ryan Ulyate, who has also produced for Electric Light Orchestra and George Harrison.

The songs were chosen by bandmates Benmont Tench and Mike Campbell, as well as Petty’s wife, Dana Petty, and daughter, Adria Petty, according to Entertainment Weekly. Campbell, former Heartbreakers’ guitarist, said he would pretend Petty was with him to hone in on his signature sound when he chose songs to be on the album, according to Rolling Stone.

Casual listeners may cast this release aside due to the obscurity of the songs; however, the compilation does an incredible job of capturing the essence of Petty’s soulful, heartfelt songwriting and irresistible charm.