[9] The album was their first with guitarist Adrian Smith, and their last with vocalist Paul Di'Anno, who was fired after problems with his stage performances arose due to his alcohol and cocaine use.

Except for "Murders in the Rue Morgue" (based on the story of the same name by Edgar Allan Poe)[12] and "Prodigal Son", the songs were written in the years prior to the recording of their debut album.

[13] Five of the album's songs featured in the band's live setlists in 1977, when Dennis Wilcock fronted Iron Maiden.

The Killer World Tour featured the band's first US shows, beginning at The Aladdin, Las Vegas, in support of Judas Priest.

All tracks are written by Steve Harris, except where notedThe song "Wrathchild" was covered in 2003 by the English metal band Sikth and featured as a B-side on their single "Scent of the Obscene".